WO2023140000A1 - Rotation detector - Google Patents
Rotation detector Download PDFInfo
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- WO2023140000A1 WO2023140000A1 PCT/JP2022/046666 JP2022046666W WO2023140000A1 WO 2023140000 A1 WO2023140000 A1 WO 2023140000A1 JP 2022046666 W JP2022046666 W JP 2022046666W WO 2023140000 A1 WO2023140000 A1 WO 2023140000A1
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- 238000001514 detection method Methods 0.000 claims description 390
- 238000012937 correction Methods 0.000 claims description 76
- 238000012545 processing Methods 0.000 claims description 63
- 238000000034 method Methods 0.000 claims description 27
- 230000008569 process Effects 0.000 claims description 25
- 230000007246 mechanism Effects 0.000 claims description 24
- 230000007704 transition Effects 0.000 claims description 5
- 230000008859 change Effects 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 25
- 238000010586 diagram Methods 0.000 description 25
- 230000005415 magnetization Effects 0.000 description 7
- 230000003247 decreasing effect Effects 0.000 description 6
- 239000000696 magnetic material Substances 0.000 description 3
- 230000005330 Barkhausen effect Effects 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 230000006399 behavior Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
- G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
Definitions
- the present disclosure relates to rotation detectors.
- Patent Document 1 discloses a batteryless rotation detector that detects and holds the rotation direction and number of rotations of a rotating shaft without receiving power supply from the outside.
- the rotation detector described in Patent Document 1 includes a magnet that rotates in synchronization with a rotating shaft, a plurality of detection coils that each receive a magnetic field from the magnet and generate a voltage pulse, and a signal processing circuit that operates by receiving power from the voltage pulse.
- a magnet that rotates in synchronization with a rotating shaft
- a plurality of detection coils that each receive a magnetic field from the magnet and generate a voltage pulse
- a signal processing circuit that operates by receiving power from the voltage pulse.
- the signal processing circuit can detect the occurrence of a "missing pulse” in which the voltage pulse is missing immediately after the rotation direction of the rotating shaft is reversed, and can estimate the correct rotational position taking this into account.
- the rotation detector described in Patent Document 1 can handle missing pulses immediately after the rotation direction of the rotating shaft is reversed, but cannot handle missing pulses caused by other factors. For example, it is conceivable that the voltage pulse will not be generated or the voltage level of the voltage pulse will be significantly reduced due to a quality problem in the parts that generate the voltage pulse, such as the detection coil. Alternatively, it is conceivable that the circuit that detects the voltage pulse breaks down.
- the present disclosure has been made to solve such problems, and the purpose of the present disclosure is to improve the accuracy of correcting the rotation speed for failure to detect the voltage pulse in a rotation detector that detects the rotation speed of the rotating shaft based on the voltage pulse generated from the detection coil.
- a rotation detector is a rotation detector that detects the rotation direction and number of rotations of a rotating shaft, and includes a rotation detecting mechanism that is attached to the rotating shaft and detects rotation of the rotating shaft, and a signal processing circuit that is electrically connected to the rotation detecting mechanism.
- the rotation detection mechanism includes a magnet and L detection coils (L is a natural number of 3 or more).
- the magnet is configured to rotate synchronously with the rotation axis, and has N (N is a natural number equal to or greater than 2) magnetic poles arranged in the direction of rotation.
- the L detection coils are arranged at positions shifted from each other by a predetermined phase along the direction of rotation of the magnet.
- Each of the L sensing coils is configured to receive a magnetic field applied from the magnet and generate a positive or negative polarity voltage pulse every half cycle of the rotation period of the magnet.
- the signal processing circuit includes a constant voltage circuit that generates a power supply voltage from the power of the voltage pulse each time a voltage pulse is generated, and a controller and nonvolatile memory that operate on the power supply voltage.
- the non-volatile memory is configured to store the state of the L detection coils when the voltage pulse is generated, the number of revolutions of the rotating shaft, and the history of the information of the detection coil that generated the voltage pulse.
- the controller acquires the states of the L detection coils, information about the detection coil that generated the voltage pulse, and the number of revolutions of the rotating shaft each time a voltage pulse is generated, and executes processing for updating the nonvolatile memory.
- the controller refers to the current voltage pulse information, the state of the L detection coils when the previous voltage pulse was generated, the state of the L detection coils when the voltage pulse was generated the last time, and the history of the information of the detection coils when the voltage pulse was generated the time before last, which are held in the nonvolatile memory, thereby detecting a missing pulse in which the voltage pulse is missing and correcting the state of the L detection coils and the rotation speed of the rotating shaft held in the nonvolatile memory.
- a rotation detector that detects the number of rotations of a rotating shaft based on voltage pulses generated from a detection coil, it is possible to increase the accuracy of correcting the number of rotations for missing voltage pulses.
- FIG. 1 is a diagram showing the overall configuration of a rotation detector according to Embodiment 1; FIG. It is a figure which shows the structural example of a rotation detection mechanism.
- FIG. 4 is a diagram schematically showing the magnetization relationship of a magnetic wire with respect to an external magnetic field; FIG. 4 is a diagram showing the relationship between an external magnetic field applied to a detection coil from a rotating magnet and a voltage pulse output from the detection coil; FIG. 4 is a waveform diagram of voltage pulses generated from a detection coil;
- FIG. 5 is a diagram showing changes in state signals of the A-phase detection coil, the B-phase detection coil, and the C-phase detection coil when the magnet is rotating; It is a figure which shows the hardware constitutions of a signal-processing circuit.
- FIG. 4 is a diagram schematically showing the magnetization relationship of a magnetic wire with respect to an external magnetic field
- FIG. 4 is a diagram showing the relationship between an external magnetic field applied to a detection coil from a rotating magnet and a voltage pulse output from
- FIG. 4 is a diagram showing a conversion table used for update processing according to the first embodiment;
- FIG. FIG. 4 is a diagram showing a conversion table used for update processing according to the first embodiment;
- FIG. FIG. 10 is a diagram illustrating an example of an occurrence pattern of missing pulses;
- FIG. 10 is a diagram showing the overall configuration of a rotation detector according to Embodiment 2;
- FIG. 10 is a diagram showing a conversion table used for update processing according to the second embodiment;
- FIG. FIG. 10 is a diagram showing a conversion table used for update processing according to the second embodiment;
- FIG. FIG. 10 is a diagram showing the overall configuration of a rotation detector according to Embodiment 3;
- FIG. 13 is a diagram showing the overall configuration of a rotation detector according to Embodiment 4;
- FIG. 1 is a diagram showing the overall configuration of a rotation detector according to Embodiment 1.
- FIG. Rotation detector 101 according to the first embodiment is a batteryless rotation detector, and is configured to detect and hold the rotation direction and number of rotations of a rotating body without being supplied with power from the outside.
- the rotation detector 101 includes a rotation detection mechanism 110 and a signal processing circuit 120.
- Signal processing circuit 120 is electrically connected to rotation detection mechanism 110 .
- the rotation detection mechanism 110 is attached to the rotating shaft 115 and configured to detect rotation of the rotating shaft 115 .
- the rotating shaft 115 is, for example, the output shaft of a motor. Note that the rotation detection mechanism 110 is not limited to the rotation shaft 115, and can be applied to a rotating body that can rotate around the axis.
- the rotation detection mechanism 110 has a magnet 111 and detection coils 112, 113, and 114.
- the magnet 111 has a disk shape and is attached concentrically to the rotating shaft 115 .
- the magnet 111 has two magnetic poles (N pole, S pole) on each half circumference.
- the magnet 111 rotates along with the rotating shaft 115 in a CW (Clockwise) direction or a CCW (Counter Clockwise) direction.
- the CW (clockwise) direction is the right rotation direction (forward rotation) when viewed from the rotation shaft 115
- the CCW (counterclockwise) direction is the left rotation direction (reverse rotation) when viewed from the rotation shaft 115 .
- the rotating shaft 115 and the magnet 111 are arranged concentrically in the example of FIG. Also, the number of magnetic poles of the magnet 111 may be two or more.
- the detection coils 112 , 113 , 114 are arranged at intervals in the rotation direction of the magnet 111 so as to surround the outer periphery of the magnet 111 .
- Each of the detection coils 112, 113, 114 is made of a magnetic wire with a large Barkhausen effect.
- a magnetic wire is constructed using a hard magnetic material on the inside of the wire and a soft magnetic material on the outside of the wire.
- the detection coil 112 is also referred to as the "A phase detection coil”
- the detection coil 113 is also referred to as the "B phase detection coil”
- the detection coil 114 is also referred to as the "C phase detection coil”. Note that the number of detection coils is not limited to three, and may be three or more.
- FIG. 2 is a diagram showing a configuration example of the rotation detection mechanism 110. As shown in FIG. The positional relationship between magnet 111 and detection coils 112, 113, and 114 will be described with reference to FIG. Furthermore, the logic for detecting the number of revolutions of the rotary shaft 115 using the rotation detection mechanism 110 will be described.
- the detection coils 112 , 113 , 114 are arranged to extend in the radial direction of the magnet 111 at positions shifted from each other by a predetermined phase in the rotation direction of the magnet 111 .
- the A-phase detection coil 112 is arranged at a position of 60° in the CW direction from the B-phase detection coil 113
- the C-phase detection coil 114 is arranged at a position of 60° in the CCW direction from the B-phase detection coil 113 with respect to the central angle of the magnet 111.
- the arrangement positions of the detection coils 112, 113, and 114 are not limited to this.
- FIG. 3 is a diagram schematically showing the relationship between the magnetization M of the magnetic wire and the external magnetic field H.
- the magnetic wire exhibits a behavior (large Barkhausen effect) in which the magnetization M is abruptly reversed when the strength of the external magnetic field H exceeds a certain value.
- the reversal speed of the magnetization M at this time is always constant regardless of how the external magnetic field H is applied.
- a detection coil made of a magnetic wire is arranged around the outer circumference of magnet 111 rotating together with rotating shaft 115, so that a constant voltage pulse can always be generated from the detecting coil regardless of the rotation speed of rotating shaft 115 (that is, magnet 111).
- FIG. 4 is a diagram showing the relationship between the external magnetic field applied to the detection coil from the rotating magnet 111 and the voltage pulse output from the detection coil.
- the upper part of FIG. 4 shows the relationship between the external magnetic field (broken line) and the voltage pulse (solid line) when the magnet 111 is rotating in the CW direction.
- the lower part of FIG. 4 shows the relationship between the external magnetic field (dashed line) and the voltage pulse (solid line) when the magnet 111 is rotating in the CCW direction.
- the external magnetic field applied to the detection coil has a sinusoidal waveform whose one period is the time for one rotation of the magnet 111.
- the detection coil generates one voltage pulse every half cycle of the external magnetic field.
- the sensing coil generates positive voltage pulses during positive half-cycles of the external magnetic field and negative voltage pulses during negative half-cycles of the external magnetic field. Therefore, by detecting this voltage pulse, rotation detector 101 can count the number of rotations of rotating shaft 115 . Further, by utilizing the power of this voltage pulse, a battery-less type rotation detector 101 can be realized.
- the timing of generating the positive and negative voltage pulses differs depending on the direction of rotation of the magnet 111 .
- the position where the voltage pulse is generated in the CW direction and the position where the voltage pulse is generated in the CCW direction are shifted by an angle ⁇ .
- each of the detection coils 112, 113, 114 arranged on the outer circumference of the magnet 111 generates positive and negative voltage pulses according to the rotation of the magnet 111 (rotating shaft 115).
- FIG. 5 is a waveform diagram of voltage pulses generated from the detection coils 112, 113 and 114.
- FIG. FIG. 5(a) is a waveform diagram of voltage pulses generated by the detection coils 112, 113, and 114 when the magnet 111 is rotating in the CW direction.
- FIG. 5(b) is a waveform diagram of voltage pulses generated by the detection coils 112, 113, and 114 when the magnet 111 is rotating in the CCW direction.
- A-phase pulse indicates the voltage pulse of the A-phase detection coil 112
- B-phase pulse indicates the voltage pulse of the B-phase detection coil 113
- C-phase pulse indicates the voltage pulse of the C-phase detection coil 114.
- FIG. 5(a) shows the waveforms of the A-phase pulse, B-phase pulse, and C-phase pulse when the magnet 111 rotates once in the CW direction, that is, when the magnet reference position changes from 0° (origin position) to 360°.
- the A-phase detection coil 112 is arranged at a position of 60°
- the B-phase detection coil 113 is arranged at the origin position (0°)
- the C-phase detection coil 114 is arranged at a position of 300°.
- each of the detection coils 112, 113, 114 generates a positive or negative voltage pulse every half cycle of the magnet 111's rotation cycle.
- the position at which each voltage pulse is generated is not the arrangement position of the corresponding detection coil, but is shifted from the arrangement position by an angle of ⁇ /2.
- the position where the positive A-phase pulse is generated is shifted by ⁇ /2 in the CW direction with respect to the arrangement position of the A-phase detection coil 112 of 60°.
- the position where the negative A-phase pulse is generated is shifted by ⁇ /2 in the CW direction with respect to the position 240° which is symmetrical with the arrangement position 60° of the A-phase detection coil 112 . This is because, as shown in FIG.
- the magnetization M of the magnetic wire is not reversed unless the external magnetic field reaches a certain strength (hereinafter also referred to as a threshold value).
- a certain strength hereinafter also referred to as a threshold value.
- FIG. 5(b) shows the waveforms of the A-phase pulse, B-phase pulse, and C-phase pulse when the magnet 111 rotates once in the CCW direction, that is, when the magnet reference position changes from 360° to 0° (origin position).
- the generation positions of the A-phase, B-phase, and C-phase pulses are not the arrangement positions of the corresponding detection coils, but positions shifted by an angle of ⁇ /2 from the arrangement positions.
- the rotation direction of the magnet 111 is the CCW direction
- the position where the voltage pulse is generated is shifted in the CCW direction from the arrangement position of the corresponding detection coil.
- each of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114 generates positive and negative voltage pulses according to the rotation of the magnet 111.
- the rotation detection mechanism 110 transmits voltage pulses output from each phase detection coil to the signal processing circuit 120 .
- the signal processing circuit 120 uses the power of the voltage pulse transmitted from the rotation detection mechanism 110 to generate a power supply voltage for the signal processing circuit 120 . Also, the signal processing circuit 120 detects the rotation direction and rotation speed of the rotating shaft 115 based on the voltage pulse.
- the rotating shaft 115 in order to detect the number of rotations of the rotating shaft 115, first, it is necessary to generate state signals indicating the states of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114.
- the state signal of each phase detection coil can be generated based on the voltage pulse generated by each phase detection coil.
- the state signal of each phase detection coil can be generated so that it rises from L (logic low) level to H (logic high) level when a positive voltage pulse is generated, and falls from H level to L level when a negative voltage pulse is generated. That is, the state signal of each phase detection coil is held at H level from the generation of the positive voltage pulse until the corresponding detection coil generates the negative voltage pulse, and is held at the L level from generation of the negative voltage pulse until generation of the positive voltage. According to this, the state signal of each phase detection coil becomes a signal representing the polarity of the last voltage pulse generated by the corresponding detection coil.
- FIG. 6 is a diagram showing changes in state signals of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114 when the magnet 111 is rotating.
- 6A shows changes in the state signals of the phase detection coils when the magnet 111 rotates in the CW direction
- FIG. 6B shows changes in the state signals of the phase detection coils when the magnet 111 rotates in the CCW direction.
- both state signals alternately change between H level and L level every 180° (half cycle).
- the rotation speed is increased by +1, and when the state signal of the C-phase detection coil 114 is at L level and the rise of the state signal of the B-phase detection coil 113 is detected, the rotation speed is decreased by -1.
- the rotation speed is increased by +1
- the state signal of the A phase detection coil 112 is at H level
- the state signal of the C phase detection coil 114 is at L level
- the rise of the state signal of the B phase detection coil 113 is detected
- the rotation speed is decreased by -1.
- the magnet reference is located in region 1.
- the state signal of the A-phase detection coil 112 is at H level
- the state signal of the B-phase detection coil 113 is at L level
- the state signal of the C-phase detection coil 114 is at L level
- FIG. 7 is a diagram showing the hardware configuration of the signal processing circuit 120.
- the signal processing circuit 120 includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 11, a ROM (Read Only Memory) 12, an I/F (Interface) device 13, and a storage device 14.
- CPU 10 , RAM 11 , ROM 12 , I/F device 13 and storage device 14 exchange various data through communication bus 15 .
- the CPU 10 expands the program stored in the ROM 12 to the RAM 11 and executes it.
- a program stored in the ROM 12 describes processing to be executed by the signal processing circuit 120 .
- the I/F device 13 is an input/output device for exchanging signals and data with the rotation detection mechanism 110 and external devices.
- the I/F device 13 receives voltage pulses output by the detection coils 112 , 113 and 114 from the rotation detection mechanism 110 .
- the storage device 14 is a storage that stores various types of information, such as information on the rotation detection mechanism 110 and information on the rotating body.
- the storage device 14 also has an updatable non-volatile memory for storing information obtained from the voltage pulse received from the rotation detection mechanism 110 (the state of the detection coil, the number of rotations of the rotary shaft 115, etc.).
- the non-volatile memory will be explained in detail later.
- All or part of the functions realized by the CPU 10 executing the program may be realized using a hard-wired circuit such as an integrated circuit.
- a hard-wired circuit such as an integrated circuit.
- it may be realized using ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or CPLD (Complex Programmable Logic Device).
- the signal processing circuit 120 includes full-wave rectifier circuits 121_A, 121_B, 121_C, a constant voltage circuit 122, an enable circuit 123, a pulse waveform sign determination circuit 124, a controller 125, an adder 126, a nonvolatile memory 127, an external circuit I/F 128, and a power supply switching circuit 129.
- the controller 125 and the adder 126 are implemented by the CPU 10 (see FIG. 7) shown in FIG. 7 executing programs.
- the signal processing circuit 120 executes the series of operations described below each time one of the detection coils 112, 113, and 114 in the rotation detection mechanism 110 outputs a voltage pulse.
- the full-wave rectifier circuit 121_A is electrically connected to the A-phase detection coil 112, full-wave rectifies the voltage pulse (A-phase pulse) output from the A-phase detection coil 112, and outputs the rectified voltage pulse to the constant voltage circuit 122.
- the full-wave rectifier circuit 121_B is electrically connected to the B-phase detection coil 113, full-wave rectifies the voltage pulse (B-phase pulse) output from the B-phase detection coil 113, and outputs the rectified voltage pulse to the constant voltage circuit 122.
- the full-wave rectifier circuit 121_C is electrically connected to the C-phase detection coil 114, full-wave rectifies the voltage pulse (C-phase pulse) output from the C-phase detection coil 114, and outputs the rectified voltage pulse to the constant voltage circuit 122.
- the constant voltage circuit 122 generates a constant voltage from the voltage pulse given from one of the full-wave rectifier circuits 121_A, 121_B, and 121_C, and supplies the generated constant voltage as a power supply voltage to the enable circuit 123, the pulse waveform sign determination circuit 124, the controller 125, the adder 126, and the nonvolatile memory 127.
- the power supply switching circuit 129 is configured to switch the power supply source for the controller 125 and the nonvolatile memory 127 between the constant voltage circuit 122 and an external power supply (not shown) provided outside the rotation detector 101 .
- the external power supply is the main power supply for driving the rotating body. According to this, power can be continuously supplied to the controller 125 and the nonvolatile memory 127 even while the rotation shaft 115 is stopped.
- the non-volatile memory 127 stores the state of each phase detection coil when the voltage pulse is generated, the rotation speed of the rotating shaft 115, and the information (detection coil number) of the detection coil that generated the voltage pulse. These pieces of information are acquired and stored in the non-volatile memory 127 each time one of the detection coils 112, 113, and 114 generates a voltage pulse. Nonvolatile memory 127 further stores a conversion table (see FIGS. 8 and 9), which will be described later.
- nonvolatile memory 127 is configured to hold at least the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that generated the previous voltage pulse, and the state of each phase detection coil when the voltage pulse before the previous time was generated and the information about the detection coil that output the voltage pulse before the previous time, with respect to the state of each phase detection coil and the information about the detection coil that generated the voltage pulse. These information are updated by controller 125 each time a voltage pulse occurs.
- the enable circuit 123 When the enable circuit 123 confirms that the voltage supplied from the constant voltage circuit 122 has stabilized, the enable circuit 123 sends a trigger signal for starting operation to the pulse waveform sign determination circuit 124, controller 125, adder 126, and nonvolatile memory 127.
- the pulse waveform sign determination circuit 124 receives a trigger signal from the enable circuit 123 and starts operating.
- the pulse waveform sign determination circuit 124 generates a detection signal for the A-phase detection coil 112 based on the voltage pulse (A-phase pulse) output from the A-phase detection coil 112, generates a detection signal for the B-phase detection coil 113 based on the voltage pulse (B-phase pulse) output from the B-phase detection coil 113, and generates a detection signal for the C-phase detection coil 114 based on the voltage pulse (C-phase pulse) output from the C-phase detection coil 114.
- the detection signal of each phase detection coil is a signal that indicates whether or not a voltage pulse is generated from each phase detection coil and the polarity of the generated voltage pulse.
- the detection signal becomes H level when the corresponding detection coil generates a positive voltage pulse, becomes L level when it generates a negative voltage pulse, and becomes 0 when no voltage pulse is generated. That is, the detection signal leaves information of voltage pulses generated by each phase detection coil as a history.
- the pulse waveform sign determination circuit 124 transmits the generated detection signal to the controller 125 .
- the controller 125 transmits the detection signal of each phase detection coil received from the pulse waveform sign determination circuit 124 to the adder 126 .
- the controller 125 further accesses the nonvolatile memory 127 to read out from the nonvolatile memory 127 the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that generated the voltage pulse, and the state of each phase detection coil when the voltage pulse was generated the last time before and the information about the detection coil that output the voltage pulse.
- the controller 125 transmits the read information to the adder 126 .
- the adder 126 updates the state and rotation speed of each phase detection coil to the latest state and rotation speed of each phase detection coil using a conversion table (see FIGS. 8 and 9), which will be described later, based on the information received from the controller 125 (the state signal of each phase detection coil when the current voltage pulse is generated and the information read from the nonvolatile memory 127).
- the adder 126 transmits to the controller 125 the latest updated state and rotation speed of each phase detection coil.
- the controller 125 When the controller 125 receives the information from the adder 126, it accesses the non-volatile memory 127 again and writes the latest state and rotation speed of each phase detection coil and the information of the detection coil that generated the current voltage pulse into the non-volatile memory 127.
- the signal processing circuit 120 executes the above-described series of operations using the power supply voltage generated from the voltage pulse each time one of the detection coils 112, 113, and 114 outputs a voltage pulse, thereby enabling the signal processing circuit 120 to detect the rotation speed of the rotating shaft 115 without a battery.
- the number of rotations of the rotating shaft 115 can be read by accessing the nonvolatile memory 127 via the external circuit I/F 128 and the controller 125.
- the controller 125 is configured to restrict access to the nonvolatile memory 127 from the outside so that the series of operations for updating the rotation speed described above do not conflict with the reading operation of the rotation speed from the outside.
- the power supply switching circuit 129 supplies power supply voltage from the external power supply (main power supply) to the controller 125 and the nonvolatile memory 127 . Further, the power supply voltage is directly supplied from the external power supply to the external circuit I/F 128 . Therefore, the rotation speed can be read without depending on the power of the voltage pulse.
- adder 126 updates the state of each phase detection coil stored in nonvolatile memory 127 and the number of rotations of rotating shaft 115 based on the voltage pulses output from each of detection coils 112, 113, and 114 in accordance with the rotation of magnet 111.
- the adder 126 is configured to perform correction processing to compensate for the missing voltage pulse during update processing.
- the update process including this correction is executed according to the conversion tables shown in FIGS. 8 and 9. FIG.
- the conversion tables shown in FIGS. 8 and 9 represent the transition of the state of each phase detection coil and the region where the magnet reference is located as the magnet 111 rotates.
- "current status" indicates the state of each phase detection coil from the previous voltage pulse to the current voltage pulse, and the region where the magnet reference estimated from the state of each phase detection coil is located.
- Previous status indicates the state of each phase detection coil from the generation of the voltage pulse before the previous to the generation of the previous voltage pulse, and the region where the magnet reference estimated from the state of each phase detection coil is located. Note that each of the current status and the previous status are updated in response to the occurrence of the current voltage pulse.
- the information before updating includes information on the detection coil that generated the voltage pulse two times before (denoted as “detection coil number two times before”) in addition to the "current status” and "previous status”.
- the updated information includes the "current status” and "previous status” as well as the correction amount of the count value of the number of revolutions of the rotating shaft 115 (denoted as “count”).
- the value “0” indicates that the number of rotations is not corrected
- the value “1” indicates that the number of rotations is increased by +1
- the value "-1” indicates that the number of rotations is decreased by -1.
- the conversion table further shows the detection signal of each of the detection coils 112, 113, and 114 (denoted as "power generation element input”).
- This detection signal is a signal generated by the above-described pulse waveform code determination circuit 124 (FIG. 1).
- a “H” indicates that the sensing coil generated a positive voltage pulse
- an “L” indicates that the sensing coil generated a negative voltage pulse
- a "0” indicates that the sensing coil did not generate a voltage pulse.
- the signal processing circuit 120 determines that a phenomenon different from the expected missing pulse has occurred, and outputs an error.
- the "missing pulse” includes a missing pulse that occurs immediately after the rotation direction of the magnet 111 is reversed and a missing pulse that occurs at a timing other than the above timing.
- the adder 126 performs correction processing for each of these two types of missing pulses.
- the reversal of the magnet 111 applies a magnetic field of opposite polarity to the magnetic field that generated the voltage pulse to the detection coil. Even when the intensity of the applied magnetic field exceeds the threshold, a phenomenon may occur in which the voltage level of the voltage pulse generated from the detection coil becomes small. When the voltage level of the voltage pulse drops significantly, the signal processing circuit 120 cannot receive the power of the voltage pulse to operate, and a missing pulse occurs. As a result, a phenomenon occurs in which the actual magnet reference position does not match the magnet reference position estimated from the state of each phase detection coil held in the nonvolatile memory 127 .
- the magnet reference moves in the CW direction from region 6 to region 1, and the strength of the magnetic field applied to the B-phase detection coil 112 exceeds the threshold. Thereby, a voltage pulse is generated from the B-phase detection coil 112 . After that, it is assumed that the magnet reference returns from the region 1 to the region 6 due to the rotation of the magnet 111 being reversed in the CCW direction immediately after the generation of the voltage pulse.
- the magnet 111 rotates in the CCW direction, so that the strength of the opposite polarity magnetic field applied to the B-phase detection coil 113 exceeds the threshold.
- the voltage level of the voltage pulse generated by the B-phase detection coil 113 is small and the signal processing circuit 120 does not operate, "missing pulse" occurs.
- controller 125 retains the state of each phase detection coil indicating that the magnet reference is located in region 1 without updating the state of each phase detection coil and the position of the magnet reference held in non-volatile memory 127 .
- non-volatile memory 127 retains the state of each phase detection coil when the magnet reference is located in Region 1.
- the adder 126 can detect that the missing pulse has occurred.
- the situation in which the C-phase detection coil 114 generates a voltage pulse while the state of each phase detection coil is maintained when the magnet reference is located in region 1 can also occur when the magnet reference moves in the CCW direction from region 2 to region 1 and immediately after that, the rotation direction of the magnet 111 reverses.
- This case is called a "second example”.
- the C-phase detection coil 114 when the magnet reference returns from region 1 to region 2, pulse missing occurs in the A-phase detection coil 112, and when the magnet 111 continues to rotate in the CW direction and the magnet reference moves to region 3, the C-phase detection coil 114 generates a voltage pulse.
- the adder 126 can detect the occurrence of the missing pulse.
- the first example and the second example since the position of the magnet reference estimated from the state of each phase detection coil when the previous voltage pulse was generated is region 1, the first example and the second example cannot be distinguished. Therefore, even if the missing pulse can be detected, the magnet-based position and rotation speed cannot be corrected.
- the position of the magnet reference which is held in the nonvolatile memory 127 and is estimated from the state of each phase detection coil when the voltage pulse was generated before the last time, is area 6 in the first example and area 2 in the second example, and both are different. Therefore, it is possible to distinguish between the first example and the second example. Specifically, in the first example, it can be estimated that the missing pulse occurs when the magnet reference moves from region 1 to region 6, and then the C-phase detection coil 114 generates a voltage pulse when the magnet reference moves from region 6 to region 5.
- the state (current status) of each phase detection coil when the previous voltage pulse was generated which is held in the nonvolatile memory 127, can be corrected to the state of each phase detection coil when the magnet reference is located in region 5, which is one region jumped in the CCW direction from region 1, and the number of rotations can be reduced by -1.
- this correction processing is indicated by "first example”.
- the state (current status) and rotation speed of each phase detection coil when the previous voltage pulse was generated, which are held in the nonvolatile memory 127 can be corrected.
- the missing pulse occurs when the magnet reference moves from region 1 to region 2, and then the C-phase detection coil 114 generates a voltage pulse when the magnet reference moves from region 2 to region 3. Therefore, the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, can be corrected to the state of each phase detection coil when the magnet reference is positioned in region 3, which is one region jumped in the CW direction from region 1.
- the rotation speed is not corrected. In the conversion table of FIG. 8, this correction processing is indicated by "second example".
- the magnet 111 may continue to rotate without reversing the direction of rotation immediately after the detection coil generates a voltage pulse, or even in a situation where the missing pulse occurs immediately after the direction of rotation of the magnet 111 is reversed and continues to rotate thereafter, the voltage level of the voltage pulse may drop and the missing pulse may occur due to quality problems or noise in the power generation and detection components. Even in this case, since the signal processing circuit 120 cannot operate by receiving the power of the voltage pulse, a missing pulse occurs. As a result, a phenomenon may occur in which the actual magnet reference position and the magnet reference position estimated from the state of each phase detection coil held in the nonvolatile memory 127 do not match.
- the B-phase detection coil 113 When the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
- the C-phase detection coil 114 when the magnet reference moves from region 2 to region 3, the C-phase detection coil 114 generates a positive voltage pulse.
- This series of voltage pulse generation patterns is the same as the voltage pulse generation pattern in the first example. Therefore, following the first example, the adder 126 presumes that the pulse missing occurred immediately after the rotation direction of the rotating shaft 115 reversed to the CCW direction, corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) held in the nonvolatile memory 127 to the state of each phase detection coil when the magnet reference is positioned in the region 5, and changes the state of each phase detection coil when the last voltage pulse was generated (previous status) to: Correction to the state of each phase detection coil when the magnet reference is positioned in region 6 is performed. Further, the adder 126 makes a correction to reduce the number of revolutions by -1. However, as is clear from FIG. 10 , this estimation and correction are different from the actual rotational motion of the magnet 111 .
- the B-phase detection coil 113 generates a positive voltage pulse.
- This pattern of voltage pulse generation is a pattern that would not normally occur if the magnet reference were positioned in region 5 . Also, this generation pattern is a pattern that cannot occur when a missing pulse occurs in the CW direction, or when a missing pulse occurs immediately after the missing pulse occurs immediately after the reversal in the CCW direction.
- the adder 126 refers to the history of the state of each phase detection coil when the previous voltage pulse was generated, the state of each phase detection coil when the voltage pulse was generated the time before last, and the information (detection coil number) of the detection coil that generated the voltage pulse last time and the time before last, which are held in the nonvolatile memory 127.
- the adder 126 presumes that the magnet 111 is rotating in the CW direction and that a missing pulse occurred when the previous voltage pulse was generated. Then, the adder 126 estimates that the position of the magnet reference when the last voltage pulse was generated is not region 5 but region 3, and updates the position of the magnet reference when the previous voltage pulse is generated to region 4.
- the adder 126 corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, to the state of each phase detection coil when the magnet reference is located in region 4, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated before the last time to the state of each phase detection coil when the magnet reference is located in region 3. Further, the adder 126 performs a correction to increase the rotational speed by +1, and stores the result in the nonvolatile memory 127 . In the conversion table of FIG. 9, this correction processing is indicated by "third example".
- a missing pulse occurs immediately after the direction of rotation of the magnet 111 is reversed, followed by another missing pulse.
- the B-phase detection coil 113 is placed at the origin position and the magnet reference is at the origin position, the magnet reference moves in the CW direction from area 6 to area 1, and then, due to the reversal of the rotation direction, the magnet reference moves in the CCW direction in the order of area 6, area 5, and area 4.
- the B-phase detection coil 113 When the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
- the nonvolatile memory 127 holds the state of each phase detection coil when the magnet reference is positioned in area 1.
- phase A detection coil 112 when the magnet reference moves from area 5 to area 4 in the CCW direction, phase A detection coil 112 generates a negative voltage pulse.
- the voltage pulse generation pattern is the same as when the magnet reference moves from region 1 to region 2 in the CW direction. Therefore, adder 126 presumes that the magnet reference is located in region 2, and holds the state of each phase detection coil when the magnet reference is located in region 2 as the current status in non-volatile memory 127 .
- the B-phase detection coil 113 when the magnet reference moves from area 4 to area 3 in the CCW direction, the B-phase detection coil 113 generates a negative voltage pulse.
- This voltage pulse generation pattern is a pattern that would not normally occur if the magnet reference were located in region 2 . Therefore, the adder 126 refers to the state of each phase detection coil when the previous voltage pulse was generated and the state of each phase detection coil when the last voltage pulse was generated, which are held in the nonvolatile memory 127, as well as the history of the detection coils (detection coil numbers) that generated the previous and two previous voltage pulses.
- the adder 126 presumes that the magnet 111 is actually rotating in the CCW direction, and that the missing pulse occurred when the previous voltage pulse was generated. In this case, the adder 126 estimates that the magnet reference position when the last voltage pulse was generated is not region 2 but region 4, and updates the magnet reference position when the previous voltage pulse was generated to region 3.
- the adder 126 corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, to the state of each phase detection coil when the magnet reference is located in region 3, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated the last time before to the state of each phase detection coil when the magnet reference is located in region 4. Further, the adder 126 performs a correction to decrease the number of revolutions by -1, and stores the result in the nonvolatile memory 127 . In the conversion table of FIG. 8, this correction processing is indicated by "fourth example".
- the controller 125 updates the history of the information (detection coil number) of the detection coil that generated the voltage pulse, and writes the other information read from the nonvolatile memory 127 to the nonvolatile memory 127 as it is. This is because when the history of the detection coil information (detection coil number) is updated, the information of the detection coil that detected the voltage pulse of the time before last, which is referred to during correction, is updated. Therefore, even if the pattern is correctable, it will no longer match the conversion pattern shown in the conversion table (see FIGS. 8 and 9), and an error will be output.
- the area where the magnet reference is actually located differs from the area where the magnet reference in the current status held in the nonvolatile memory 127 is located. Therefore, if the number of revolutions is read out during this period, the read number of revolutions may not match the actual number of revolutions.
- an external power supply for example, an optical, mechanical, or magnetic encoder
- the area where the magnet reference is located is compared with the area where the magnet reference stored in the nonvolatile memory 127 is located, and if they do not match, an error is output, thereby preventing the number of revolutions before correction from being read out.
- mismatch it is preferable to judge whether or not not only the area where the current magnet reference is located but also the area where the previous magnet reference is located match, considering the case where the pulse missing due to the reversal of the rotation direction occurs.
- the area where the magnet reference is located when the previous voltage pulse was generated can be uniquely determined by having information on which direction, CW/CCW, the magnet reference has moved to the current position. Therefore, the amount of information stored in the nonvolatile memory 127 can be reduced by using the information indicating the magnet-based moving direction.
- information on the detection coil that generated the voltage pulse before the last can be obtained from the difference between the area where the previous magnet reference is located and the area where the magnet reference before the previous is located, so the information on the difference may be used.
- the controller 125 does not update the information in the nonvolatile memory 127, and in processing the next generated voltage pulse, it is possible to handle it in the same way as if the inversion pulse was missing.
- the rotation detector by referring to the history of the current voltage pulse (polarity and detection coil), the state of each phase detection coil when the previous voltage pulse was generated, the state of each phase detection coil when the voltage pulse was generated before the previous time, and the information (detection coil number) of the detection coil that generated the voltage pulse the last time and the time before the time before, which are held in the nonvolatile memory 127, is generated at the timing immediately after the rotation direction of the magnet 111 is reversed. It is possible to detect not only missing pulses but also missing pulses that occur at timings other than the above timings.
- the state of each phase detection coil (position based on the magnet) and the rotation speed of the rotating shaft 115 held in the nonvolatile memory 127 can be corrected using the above information. As a result, it is possible to improve the accuracy of correcting the number of revolutions for missing pulses.
- FIG. 11 is a diagram showing the overall configuration of the rotation detector according to the second embodiment. As shown in FIG. 11, rotation detector 101A according to the second embodiment differs from rotation detector 101 shown in FIG.
- the signal processing circuit 120A replaces the controller 125, adder 126 and nonvolatile memory 127 in the signal processing circuit 120 shown in FIG.
- the non-volatile memory 127A is configured to store a "correction execution flag" indicating that correction has been performed in the previous update process, in addition to a history of the number of rotations of the rotary shaft 115, the state of each phase detection coil when a voltage pulse is generated, and information (detection coil number) of the detection coil that generated the voltage pulse.
- Nonvolatile memory 127A further stores conversion tables shown in FIGS.
- the correction implementation flag is added to the updated information in the conversion tables shown in FIGS.
- the correction execution flag is set to "1" when correction is executed in the previous update process, and is set to "0" when correction is not executed.
- the controller 125A accesses the non-volatile memory 127A and reads from the non-volatile memory 127A the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that output the voltage pulse, the state of each phase detection coil when the voltage pulse was generated the last time before, the information about the detection coil that output the voltage pulse, and the correction execution flag.
- the controller 125 transmits the read information to the adder 126 .
- the adder 126A executes update processing using the conversion table (see FIGS. 12 and 13) based on the information received from the controller 125A (the current voltage pulse information and the information read from the nonvolatile memory 127A).
- the adder 126A sets the correction execution flag to 1 when the process of correcting the state of each phase detection coil (the magnet reference position) held in the nonvolatile memory 127A is performed. Further, the adder 126A outputs an error when the correction execution flag read from the nonvolatile memory 127A is 1 and the update process for correcting the magnet-based position is performed in the update process.
- the controller 125A accesses the non-volatile memory 127A again and writes the history of the information received from the adder 126A and the updated information of the detection coil into the non-volatile memory 127A.
- phase C detection coil 114 when the magnet reference moves in the CW direction from region 5 to region 6, phase C detection coil 114 generates a negative voltage pulse. Additionally, when the magnet reference moves CW from region 6 to region 1, phase B detection coil 113 generates a negative voltage pulse. Along with this, the adder 126A increases the rotational speed by +1.
- the magnet reference moves from area 1 to area 2 in the CW direction, but due to quality problems or noise, the A-phase detection coil 112 does not generate a voltage pulse, which is a missing pulse. Due to this missing pulse, the nonvolatile memory 127A retains the state of each phase detection coil when the magnet reference position is region 1 .
- the adder 126A performs correction using the information that the C-phase detection coil 114 generated the voltage pulse of the time before last according to the conversion tables of FIGS. At this time, the adder 126A sets the correction execution flag to 1.
- the adder 126A estimates that the magnet reference position when the last voltage pulse was generated is not area 1 but area 4, and updates the magnet reference position when the previous voltage pulse was generated to area 5. Specifically, the adder 126A corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127A, to the state of each phase detection coil when the magnet reference is located in region 5, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated before the previous time to the state of each phase detection coil when the magnet reference is located in region 4.
- this process is not a process of correcting to the actual magnet reference position, but an erroneous correction.
- This voltage pulse generation pattern is a pattern that normally cannot occur when the magnet reference is located in region 5 . 12 and 13, it is assumed that the magnet reference is located in region 1 instead of region 5, the updated region is moved to region 6, and the number of revolutions is decreased by -1. However, although the position of the magnet reference is finally returned to the actual position by the two correction processes described above, the number of revolutions becomes one less than the actual number of revolutions.
- the rotation detector according to the second embodiment it is possible to avoid erroneous detection of the number of rotations caused by a combination of missing pulses in the detection coil and reversing the rotation direction a plurality of times by referring to the correction execution flag. As a result, it is possible to eliminate restrictions on the rotation direction of the rotating shaft 115 .
- FIG. 14 is a diagram showing the overall configuration of a rotation detector according to Embodiment 3.
- FIG. 14 rotation detector 101B according to the third embodiment differs from rotation detector 101 shown in FIG.
- the signal processing circuit 120B is obtained by replacing the controller 125 in the signal processing circuit 120 shown in FIG. 1 with a controller 125B.
- the controller 125B accesses the non-volatile memory 127 and reads from the non-volatile memory 127 the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information of the detection coil that output the voltage pulse (detection coil number), and the state of each phase detection coil when the voltage pulse was generated two before before and the information of the detection coil that output the voltage pulse (detection coil number).
- the controller 125B transmits the read information to the adder 126.
- the controller 125B accesses the non-volatile memory 127 again and writes the information from the adder 126 and the updated detection coil information into the non-volatile memory 127.
- the controller 125B determines whether or not the information about the detection coil that generated the previous voltage pulse is the same as the information about the detection coil that generated the current voltage pulse. If these two pieces of information are the same, the controller 125B writes the information read from the nonvolatile memory 127 without updating the information held in the nonvolatile memory 127 . Alternatively, if the non-volatile memory 127 is a non-destructive read-out memory, the controller 125B holds the previous value without writing. On the other hand, if the above two pieces of information are different, the controller 125B performs normal update processing, and writes the state of each phase detection coil, the number of revolutions, and the detection coil information to the nonvolatile memory 127 .
- Embodiment 3 even patterns that could not be corrected in Embodiments 1 and 2 described above are corrected, and the operation of the rotation detector 101B can be continued. Update processing according to the third embodiment will be described below.
- the B-phase detection coil 113 is arranged at the origin position and the magnet reference is at the origin position, and the magnet reference moves in the CW direction from area 6 to area 1, area 2, and area 3 in order, and then the rotation direction of the magnet 111 is reversed, and the magnet reference moves in the CCW direction from area 3 to area 2 and then to area 1 in order.
- the B-phase detection coil 113 When the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
- the magnet reference moves in the CW direction from area 1 to area 2, but due to quality, noise, or the like, no voltage pulse is generated in the A-phase detection coil 112, causing a missing pulse. Due to this missing pulse, the nonvolatile memory 127 retains the state of each phase detection coil when the magnet reference position is region 1 .
- the C-phase detection coil 114 When the magnet reference moves in the CW direction from region 2 to region 3, the C-phase detection coil 114 generates a positive voltage pulse.
- the voltage pulse generation pattern is the same as the "first example" described in the first embodiment. Therefore, the adder 126 presumes that the missing pulse has occurred immediately after the rotation direction is reversed, corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) to the state of each phase detection coil when the magnet reference is located in region 5, and corrects the state of each phase detection coil when the voltage pulse was generated the last time (previous status) to the state of each phase detection coil when the magnet reference is located in region 6. Further, the adder 126 reduces the number of revolutions by -1.
- the C-phase detection coil 114 After that, when the rotation direction of the magnet 111 reverses to the CCW direction and the magnet reference returns from region 3 to region 2, the C-phase detection coil 114 generates a negative voltage pulse. At this time, since the detection coil that generated the previous voltage pulse and the detection coil that generated the current voltage pulse are the same C-phase detection coil 114, the adder 126 does not update the magnet reference area and detection coil information.
- the adder 126 refers to the information history of the detection coil that generated the voltage pulse.
- the adder 126 presumes that a missing pulse different from a missing reversal occurred when the previous voltage pulse held in the non-volatile memory 127 was generated, not when the previous voltage pulse was actually generated, and that the magnet reference actually moved in the CW direction.
- the adder 126 presumes that the position of the magnet reference when the last voltage pulse was generated was not the region 5 but the region 3, and the missing pulse occurred immediately after the rotation direction was reversed from there, and the magnet reference moved in the CCW direction as it was. Therefore, the adder 126 moves the position of the magnet reference when the previous voltage pulse was generated, which is stored in the nonvolatile memory 127, to region 1, and corrects the rotational speed by +1.
- the adder 126 corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) to the state of each phase detection coil when the magnet reference is located in region 1, and also corrects the state of each phase detection coil when the last voltage pulse was generated (previous status) to the state of each phase detection coil when the magnet reference is located in region 2, and stores them in the nonvolatile memory 127. Further, the adder 126 performs a correction to increase the rotational speed by +1, and stores the result in the nonvolatile memory 127 .
- FIG. 15 is a diagram showing the overall configuration of the rotation detector according to the fourth embodiment. As shown in FIG. 15, rotation detector 101C according to the fourth embodiment differs from rotation detector 101 shown in FIG.
- the signal processing circuit 120C replaces the controller 125, adder 126 and nonvolatile memory 127 in the signal processing circuit 120 shown in FIG. 1 with a controller 125C, adder 126C and nonvolatile memory 127C, respectively.
- the nonvolatile memory 127C is configured to store correction history information in addition to the history of the number of rotations of the rotating shaft 115, the state of each phase detection coil when a voltage pulse is generated, and the information (detection coil number) of the detection coil that generated the voltage pulse.
- the correction history information includes information on the state of each phase detection coil when the correction was performed and on the detected missing pulse. The correction history is updated each time the correction is performed.
- the nonvolatile memory 127C has a correction execution counter and a pulse detection counter.
- the correction implementation counter is configured to count and store the number of times the correction is implemented.
- the pulse detection counter is configured to count and store the number of times a voltage pulse has occurred.
- the controller 125C has access to non -volatile memory 127c, the rotation axis 115 when the previous voltage pulse occurs, the status of each phase detection coil at the time of the previous voltage pulse, the detection coil that outputs the voltage pulse, and the status of each phase coil when the voltage pulse is generated two times. And the information of the detection coil that outputs the voltage pulse, the count value of the correction implementation counter and the pulse detection counter, and the correction history are read from non -volatile memory 127c. The controller 125C transmits the read information to the adder 126C.
- the adder 126C executes update processing using the conversion table (FIGS. 12 and 13) based on the information received from the controller 125C (current voltage pulse information and information read from the nonvolatile memory 127C). In this update process, the adder 126C increments the count value of the pulse detection counter by one.
- the adder 126C further increments the count value of the correction execution counter by 1 when performing the process of correcting the state of each phase detection coil (the magnet-based position) stored in the nonvolatile memory 127C in the update process, and acquires the state of each phase detection coil at the time of correction and the information on the detection coil at the time when it is estimated that a missing pulse has occurred as a correction history.
- the adder 126C compares the count value of the pulse detection counter and the count value of the correction execution counter. If the ratio of the count value of the correction counter to the count value of the pulse detection counter (count value of correction counter/count value of pulse detection counter) exceeds a predetermined threshold value, the adder 126C outputs an error because there is concern that an abnormality has occurred in the environment, parts, or the like.
- the adder 126C outputs an error when the ratio exceeds 1/2 to the 20th power as a threshold value. If the count value of the pulse detection counter reaches the upper limit before the ratio reaches the threshold, each of the pulse detection counter and the correction execution counter right-shifts the count value by 1 bit to halve the count value and continue counting up. Note that the method of adjusting the count value is not limited to the right shift described above, and a method of initializing each counter or adjusting the count value to an arbitrary value can be applied.
- the controller 125C accesses the non-volatile memory 127C again, and writes the information received from the adder 126C (including the count value and correction history) and the history of the updated detection coil information to the non-volatile memory 127C.
- the adder 126C is configured to output an error even when the corrections described in the first and third embodiments can be performed. According to this, the operation of the apparatus cannot be continued, but the apparatus can be safely stopped before an abnormality that cannot be corrected occurs. Further, by storing correction history information in the non-volatile memory 127C, it is possible to obtain information leading to identification of the factor location.
- the criterion for determining whether the adder 126C outputs an error is not limited to the above ratio.
- the pulse detection counter is not mounted in the nonvolatile memory 127C, but only the correction counter is mounted, and when the count value of the correction counter exceeds a predetermined threshold value, the adder 126C outputs an error.
- the adder 126C may also be configured to issue a warning to prompt maintenance and inspection of the device through an external device while continuing the operation of the device, instead of outputting an error. Furthermore, the adder 126C can write correction history information to a predetermined address in the nonvolatile memory 127C without reading the correction history information from the nonvolatile memory 127C.
- each embodiment can be combined, modified, or omitted as appropriate.
- the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.
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Abstract
Detecting coils (112 to 114) generate a positive or negative voltage pulse. Each time a voltage pulse is generated, a controller (125) receives electric power of the voltage pulse, and operates to acquire states of the detecting coils, information relating to the detecting coil that generated the voltage pulse, and a rotational speed of a rotating shaft (115), and updates a non-volatile memory (127). During the update, the controller (125) detects a pulse omission with reference to information relating to the current voltage pulse, a history of the states of the detecting coils when the last voltage pulse and the last-but-one voltage pulse were generated, and a history of information relating to the detecting coil that generated the last-but-one voltage pulse, said histories being held in the non-volatile memory (127), and corrects the states of the detecting coils and the rotational speed, held in the non-volatile memory (127).
Description
本開示は、回転検出器に関する。
The present disclosure relates to rotation detectors.
国際公開第2013/157279号(特許文献1)には、外部からの電力供給を受けることなく、回転軸の回転方向および回転数を検出して保持するバッテリレス方式の回転検出器が開示されている。
International Publication No. 2013/157279 (Patent Document 1) discloses a batteryless rotation detector that detects and holds the rotation direction and number of rotations of a rotating shaft without receiving power supply from the outside.
特許文献1に記載される回転検出器は、回転軸と同期して回転する磁石と、各々が磁石からの磁界を受けて電圧パルスを発生する複数の検出コイルと、電圧パルスから電力の供給を受けて動作する信号処理回路とを備えている。特許文献1では、複数の検出コイルの何れかが電圧パルスを発生する毎に、当該電圧パルスから推定される磁石の回転位置を不揮発性メモリに保持する。現在の磁石の回転位置だけでなく前回の回転位置を不揮発性メモリに保持することにより、信号処理回路は、回転軸の回転方向が反転した直後に電圧パルスが欠落する「パルス抜け」が発生したことを検知し、それを考慮した正しい回転位置を推定することができる。
The rotation detector described in Patent Document 1 includes a magnet that rotates in synchronization with a rotating shaft, a plurality of detection coils that each receive a magnetic field from the magnet and generate a voltage pulse, and a signal processing circuit that operates by receiving power from the voltage pulse. In Patent Literature 1, each time one of a plurality of detection coils generates a voltage pulse, the rotational position of the magnet estimated from the voltage pulse is stored in a nonvolatile memory. By storing not only the current rotational position of the magnet but also the previous rotational position in a non-volatile memory, the signal processing circuit can detect the occurrence of a "missing pulse" in which the voltage pulse is missing immediately after the rotation direction of the rotating shaft is reversed, and can estimate the correct rotational position taking this into account.
しかしながら、特許文献1に記載される回転検出器では、回転軸の回転方向が反転した直後のパルス抜けには対応することができるが、それ以外の要因で発生するパルス抜けには対応することができないという課題がある。例えば、検出コイルなどの電圧パルスを発生する部品の品質上のトラブルによって電圧パルスが発生しない、または、電圧パルスの電圧レベルが著しく低下するという事態が考えられる。あるいは、電圧パルスを検出する回路が故障する事態が考えられる。
However, the rotation detector described in Patent Document 1 can handle missing pulses immediately after the rotation direction of the rotating shaft is reversed, but cannot handle missing pulses caused by other factors. For example, it is conceivable that the voltage pulse will not be generated or the voltage level of the voltage pulse will be significantly reduced due to a quality problem in the parts that generate the voltage pulse, such as the detection coil. Alternatively, it is conceivable that the circuit that detects the voltage pulse breaks down.
このような事態が発生した場合、特許文献1に記載される回転検出器は、想定外の動作となるために回転位置を推定することができず、結果的にエラーを出力する。一度エラーが発生すると、エンコーダを組み込んだ装置の稼働を継続させることができなくなるため、装置を止めて復旧させる作業が必要となる。そのため、装置を稼働できないことによる損害が発生することが懸念される。
When such a situation occurs, the rotation detector described in Patent Document 1 cannot estimate the rotational position due to unexpected operation, and outputs an error as a result. Once an error occurs, it becomes impossible to continue the operation of the device incorporating the encoder, so it is necessary to stop the device and restore it. Therefore, there is concern that damage may occur due to the inability to operate the device.
本開示は、かかる課題を解決するためになされたものであり、本開示の目的は、検出コイルから発生する電圧パルスに基づいて回転軸の回転数を検出する回転検出器において、電圧パルスの検出抜けに対する回転数の補正精度を高めることである。
The present disclosure has been made to solve such problems, and the purpose of the present disclosure is to improve the accuracy of correcting the rotation speed for failure to detect the voltage pulse in a rotation detector that detects the rotation speed of the rotating shaft based on the voltage pulse generated from the detection coil.
本開示に従う回転検出器は、回転軸の回転方向および回転数を検出する回転検出器であって、回転軸に取り付けられて回転軸の回転を検出する回転検出機構と、回転検出機構と電気的に接続される信号処理回路とを備える。回転検出機構は、磁石と、L個(Lは3以上の自然数)の検出コイルとを含む。磁石は、回転軸と同期して回転するように構成され、回転方向に配置されたN個(Nは2以上の自然数)の磁極を有する。L個の検出コイルは、磁石の回転方向に沿って予め定められた位相だけ互いにずれた位置に配置される。L個の検出コイルの各々は、磁石から印加される磁界を受けて磁石の回転周期の半周期毎に正または負の極性の電圧パルスを発生するように構成される。信号処理回路は、電圧パルスが発生する毎に、当該電圧パルスの電力から電源電圧を生成する定電圧回路と、電源電圧を受けて動作するコントローラおよび不揮発性メモリとを含む。不揮発性メモリは、電圧パルスを発生したときのL個の検出コイルの状態、回転軸の回転数、および、当該電圧パルスを発生した検出コイルの情報の履歴を記憶するように構成される。コントローラは、電圧パルスが発生する毎に、L個の検出コイルの状態、当該電圧パルスを発生した検出コイルの情報、および回転軸の回転数を取得して前記不揮発性メモリを更新する処理を実行するように構成される。更新する処理において、コントローラは、今回の電圧パルスの情報と、不揮発性メモリに保持されている、前回の電圧パルスを発生したときのL個の検出コイルの状態、前々回の電圧パルスを発生したときのL個の検出コイルの状態、および、前々回の電圧パルスを発生した検出コイルの情報の履歴とを参照することにより、電圧パルスが欠落するパルス抜けを検知するとともに、不揮発性メモリに保持されるL個の検出コイルの状態および回転軸の回転数を補正する。
A rotation detector according to the present disclosure is a rotation detector that detects the rotation direction and number of rotations of a rotating shaft, and includes a rotation detecting mechanism that is attached to the rotating shaft and detects rotation of the rotating shaft, and a signal processing circuit that is electrically connected to the rotation detecting mechanism. The rotation detection mechanism includes a magnet and L detection coils (L is a natural number of 3 or more). The magnet is configured to rotate synchronously with the rotation axis, and has N (N is a natural number equal to or greater than 2) magnetic poles arranged in the direction of rotation. The L detection coils are arranged at positions shifted from each other by a predetermined phase along the direction of rotation of the magnet. Each of the L sensing coils is configured to receive a magnetic field applied from the magnet and generate a positive or negative polarity voltage pulse every half cycle of the rotation period of the magnet. The signal processing circuit includes a constant voltage circuit that generates a power supply voltage from the power of the voltage pulse each time a voltage pulse is generated, and a controller and nonvolatile memory that operate on the power supply voltage. The non-volatile memory is configured to store the state of the L detection coils when the voltage pulse is generated, the number of revolutions of the rotating shaft, and the history of the information of the detection coil that generated the voltage pulse. The controller acquires the states of the L detection coils, information about the detection coil that generated the voltage pulse, and the number of revolutions of the rotating shaft each time a voltage pulse is generated, and executes processing for updating the nonvolatile memory. In the updating process, the controller refers to the current voltage pulse information, the state of the L detection coils when the previous voltage pulse was generated, the state of the L detection coils when the voltage pulse was generated the last time, and the history of the information of the detection coils when the voltage pulse was generated the time before last, which are held in the nonvolatile memory, thereby detecting a missing pulse in which the voltage pulse is missing and correcting the state of the L detection coils and the rotation speed of the rotating shaft held in the nonvolatile memory.
本開示によれば、検出コイルから発生する電圧パルスに基づいて回転軸の回転数を検出する回転検出器において、電圧パルスの欠落に対する回転数の補正精度を高めることができる。
According to the present disclosure, in a rotation detector that detects the number of rotations of a rotating shaft based on voltage pulses generated from a detection coil, it is possible to increase the accuracy of correcting the number of rotations for missing voltage pulses.
以下、本開示の実施の形態について、図面を参照しながら詳細に説明する。なお、図中の同一または相当部分には同一符号を付してその説明は繰り返さない。
Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.
実施の形態1.
(回転検出器の全体構成)
図1は、実施の形態1に従う回転検出器の全体構成を示す図である。実施の形態1に従う回転検出器101は、バッテリレス方式の回転検出器であり、外部からの電力供給を受けることなく、回転体の回転方向および回転数を検出して保持するように構成される。Embodiment 1.
(Overall Configuration of Rotation Detector)
FIG. 1 is a diagram showing the overall configuration of a rotation detector according toEmbodiment 1. FIG. Rotation detector 101 according to the first embodiment is a batteryless rotation detector, and is configured to detect and hold the rotation direction and number of rotations of a rotating body without being supplied with power from the outside.
(回転検出器の全体構成)
図1は、実施の形態1に従う回転検出器の全体構成を示す図である。実施の形態1に従う回転検出器101は、バッテリレス方式の回転検出器であり、外部からの電力供給を受けることなく、回転体の回転方向および回転数を検出して保持するように構成される。
(Overall Configuration of Rotation Detector)
FIG. 1 is a diagram showing the overall configuration of a rotation detector according to
図1に示すように、回転検出器101は、回転検出機構110と、信号処理回路120とを備える。信号処理回路120は回転検出機構110と電気的に接続されている。
As shown in FIG. 1, the rotation detector 101 includes a rotation detection mechanism 110 and a signal processing circuit 120. Signal processing circuit 120 is electrically connected to rotation detection mechanism 110 .
回転検出機構110は、回転軸115に取り付けられ、回転軸115の回転を検出するように構成される。回転軸115は、例えば、モーターの出力軸である。なお、回転検出機構110は、回転軸115に限定されず、軸回り方向に回転可能な回転体に適用することが可能である。
The rotation detection mechanism 110 is attached to the rotating shaft 115 and configured to detect rotation of the rotating shaft 115 . The rotating shaft 115 is, for example, the output shaft of a motor. Note that the rotation detection mechanism 110 is not limited to the rotation shaft 115, and can be applied to a rotating body that can rotate around the axis.
回転検出機構110は、磁石111と、検出コイル112,113,114とを有する。磁石111は、円板の形状を有しており、回転軸115に同心状に取り付けられる。磁石111は、半円周ずつ2つの磁極(N極、S極)を有している。磁石111は、回転軸115とともに、CW(Clock Wise:時計回り)方向またはCCW(Counter Clock Wise:反時計回り)方向に回転する。CW(時計回り)方向とは、回転軸115から見て右回転方向(正転)であり、CCW(反時計回り)方向とは、回転軸115から見て左回転方向(逆転)である。
The rotation detection mechanism 110 has a magnet 111 and detection coils 112, 113, and 114. The magnet 111 has a disk shape and is attached concentrically to the rotating shaft 115 . The magnet 111 has two magnetic poles (N pole, S pole) on each half circumference. The magnet 111 rotates along with the rotating shaft 115 in a CW (Clockwise) direction or a CCW (Counter Clockwise) direction. The CW (clockwise) direction is the right rotation direction (forward rotation) when viewed from the rotation shaft 115 , and the CCW (counterclockwise) direction is the left rotation direction (reverse rotation) when viewed from the rotation shaft 115 .
図1の例では、回転軸115および磁石111を同心状に配置しているが、回転軸115の回動に同期して磁石111が回動する構成であればよい。また、磁石111の磁極の数は2以上であってもよい。
Although the rotating shaft 115 and the magnet 111 are arranged concentrically in the example of FIG. Also, the number of magnetic poles of the magnet 111 may be two or more.
検出コイル112,113,114は、磁石111の外周を囲むように、磁石111の回転方向に間隔をあけて配置される。検出コイル112,113,114の各々は、大バルクハウゼン効果を有する磁性ワイヤで形成されている。磁性ワイヤは、ワイヤ内部にハード磁性体を用い、かつ、ワイヤの外部にソフト磁性体を用いて構成される。以下の説明では、検出コイル112を「A相検出コイル」とも称し、検出コイル113を「B相検出コイル」とも称し、検出コイル114を「C相検出コイル」とも称する。なお、検出コイルの数は3に限定されず、3以上であればよい。
The detection coils 112 , 113 , 114 are arranged at intervals in the rotation direction of the magnet 111 so as to surround the outer periphery of the magnet 111 . Each of the detection coils 112, 113, 114 is made of a magnetic wire with a large Barkhausen effect. A magnetic wire is constructed using a hard magnetic material on the inside of the wire and a soft magnetic material on the outside of the wire. In the following description, the detection coil 112 is also referred to as the "A phase detection coil", the detection coil 113 is also referred to as the "B phase detection coil", and the detection coil 114 is also referred to as the "C phase detection coil". Note that the number of detection coils is not limited to three, and may be three or more.
(回転検出機構の構成)
次に、図1に示した回転検出機構110の構成および動作について説明する。 (Configuration of Rotation Detection Mechanism)
Next, the configuration and operation ofrotation detection mechanism 110 shown in FIG. 1 will be described.
次に、図1に示した回転検出機構110の構成および動作について説明する。 (Configuration of Rotation Detection Mechanism)
Next, the configuration and operation of
図2は、回転検出機構110の構成例を示す図である。図2を用いて、磁石111と検出コイル112,113,114との位置関係について説明する。さらに、回転検出機構110を用いた回転軸115の回転数の検出ロジックについて説明する。
FIG. 2 is a diagram showing a configuration example of the rotation detection mechanism 110. As shown in FIG. The positional relationship between magnet 111 and detection coils 112, 113, and 114 will be described with reference to FIG. Furthermore, the logic for detecting the number of revolutions of the rotary shaft 115 using the rotation detection mechanism 110 will be described.
図2に示すように、検出コイル112,113,114は、磁石111の回転方向に予め定められた位相だけ互いにずれた位置において、磁石111の径方向に延在するように配置される。図2の例では、磁石111の中心角において、B相検出コイル113からCW方向に60°の位置にA相検出コイル112が配置され、B相検出コイル113からCCW方向に60°の位置にC相検出コイル114が配置されている。ただし、検出コイル112,113,114の配置位置はこれに限定するものではない。
As shown in FIG. 2 , the detection coils 112 , 113 , 114 are arranged to extend in the radial direction of the magnet 111 at positions shifted from each other by a predetermined phase in the rotation direction of the magnet 111 . In the example of FIG. 2, the A-phase detection coil 112 is arranged at a position of 60° in the CW direction from the B-phase detection coil 113, and the C-phase detection coil 114 is arranged at a position of 60° in the CCW direction from the B-phase detection coil 113 with respect to the central angle of the magnet 111. However, the arrangement positions of the detection coils 112, 113, and 114 are not limited to this.
そして、検出コイル112,113,114の配置に応じて、磁石111の周方向に沿って、「原点位置(0°)」を基準とした6つの角度領域が形成される。具体的には、B相検出コイル113の配置位置を「原点位置」として、CW方向に60°毎に「領域1」から「領域6」が形成される。また、磁石111において、CW方向にS極からN極に変化する角度位置を「磁石基準」とする。
Then, according to the arrangement of the detection coils 112, 113, and 114, along the circumferential direction of the magnet 111, six angular regions are formed with the "origin position (0°)" as a reference. Specifically, with the arrangement position of the B-phase detection coil 113 set as the "origin position", "area 1" to "area 6" are formed at intervals of 60° in the CW direction. Further, the angular position at which the magnet 111 changes from the S pole to the N pole in the CW direction is defined as a "magnet reference".
検出コイル112,113,114の各々を構成する磁性ワイヤにおいて、ソフト磁性体は、図3に示すような磁化特性を有している。図3は、外部磁界Hに対する磁性ワイヤの磁化Mの関係を模式的に示す図である。図3に示すように、磁性ワイヤは、外部磁界Hの強度がある値を超えたときに磁化Mが急激に反転する振る舞い(大バルクハウゼン効果)を示す。このときの磁化Mの反転速度は、外部磁界Hの加え方によらず、常に一定となる。そこで、本実施の形態では、この磁化特性を利用して、回転軸115とともに回転する磁石111の外周に磁性ワイヤからなる検出コイルを配置することにより、回転軸115(すなわち、磁石111)の回転速度に依存せずに、常に一定の電圧パルスを検出コイルから発生させることが可能となる。
In the magnetic wires that constitute each of the detection coils 112, 113, and 114, the soft magnetic material has magnetization characteristics as shown in FIG. FIG. 3 is a diagram schematically showing the relationship between the magnetization M of the magnetic wire and the external magnetic field H. As shown in FIG. As shown in FIG. 3, the magnetic wire exhibits a behavior (large Barkhausen effect) in which the magnetization M is abruptly reversed when the strength of the external magnetic field H exceeds a certain value. The reversal speed of the magnetization M at this time is always constant regardless of how the external magnetic field H is applied. Therefore, in the present embodiment, by utilizing this magnetization characteristic, a detection coil made of a magnetic wire is arranged around the outer circumference of magnet 111 rotating together with rotating shaft 115, so that a constant voltage pulse can always be generated from the detecting coil regardless of the rotation speed of rotating shaft 115 (that is, magnet 111).
図4は、回転する磁石111から検出コイルに加わる外部磁界と、検出コイルから出力される電圧パルスとの関係を示す図である。図4の上段には、磁石111がCW方向に回転しているときの外部磁界(破線)と電圧パルス(実線)との関係が示される。図4の下段には、磁石111がCCW方向に回転しているときの外部磁界(破線)と電圧パルス(実線)との関係が示される。
FIG. 4 is a diagram showing the relationship between the external magnetic field applied to the detection coil from the rotating magnet 111 and the voltage pulse output from the detection coil. The upper part of FIG. 4 shows the relationship between the external magnetic field (broken line) and the voltage pulse (solid line) when the magnet 111 is rotating in the CW direction. The lower part of FIG. 4 shows the relationship between the external magnetic field (dashed line) and the voltage pulse (solid line) when the magnet 111 is rotating in the CCW direction.
図4に示すように、回転軸115とともに磁石111が一定速度で回転している場合、検出コイルに加わる外部磁界は、磁石111が1回転する時間を1周期とする正弦波状の波形となる。
As shown in FIG. 4, when the magnet 111 rotates at a constant speed together with the rotating shaft 115, the external magnetic field applied to the detection coil has a sinusoidal waveform whose one period is the time for one rotation of the magnet 111.
検出コイルは、外部磁界の半周期ごとに1つの電圧パルスを発生する。検出コイルは、外部磁界の正の半周期において正の電圧パルスを発生し、外部磁界の負の半周期において負の電圧パルスを発生する。したがって、この電圧パルスを検出することによって、回転検出器101は、回転軸115の回転数をカウントすることが可能となる。また、この電圧パルスの電力を利用することにより、バッテリレス方式の回転検出器101を実現することができる。
The detection coil generates one voltage pulse every half cycle of the external magnetic field. The sensing coil generates positive voltage pulses during positive half-cycles of the external magnetic field and negative voltage pulses during negative half-cycles of the external magnetic field. Therefore, by detecting this voltage pulse, rotation detector 101 can count the number of rotations of rotating shaft 115 . Further, by utilizing the power of this voltage pulse, a battery-less type rotation detector 101 can be realized.
なお、磁石111の回転方向によって、正および負の電圧パルスの発生タイミングが異なっている。図4では、CW方向での電圧パルスの発生位置と、CCW方向での電圧パルスの発生位置とは角度φだけずれている。
It should be noted that the timing of generating the positive and negative voltage pulses differs depending on the direction of rotation of the magnet 111 . In FIG. 4, the position where the voltage pulse is generated in the CW direction and the position where the voltage pulse is generated in the CCW direction are shifted by an angle φ.
図2に戻って、磁石111の外周に配置された検出コイル112,113,114の各々は、磁石111(回転軸115)の回転に応じて、正および負の電圧パルスを発生する。図5は、検出コイル112,113,114から発生する電圧パルスの波形図である。図5(a)は、磁石111がCW方向に回転しているときに検出コイル112,113,114が発生する電圧パルスの波形図である。図5(b)は、磁石111がCCW方向に回転しているときに検出コイル112,113,114が発生する電圧パルスの波形図である。なお、各図において、「A相パルス」はA相検出コイル112の電圧パルスを示し、「B相パルス」はB相検出コイル113の電圧パルスを示し、「C相パルス」はC相検出コイル114の電圧パルスを示す。
Returning to FIG. 2, each of the detection coils 112, 113, 114 arranged on the outer circumference of the magnet 111 generates positive and negative voltage pulses according to the rotation of the magnet 111 (rotating shaft 115). FIG. 5 is a waveform diagram of voltage pulses generated from the detection coils 112, 113 and 114. FIG. FIG. 5(a) is a waveform diagram of voltage pulses generated by the detection coils 112, 113, and 114 when the magnet 111 is rotating in the CW direction. FIG. 5(b) is a waveform diagram of voltage pulses generated by the detection coils 112, 113, and 114 when the magnet 111 is rotating in the CCW direction. In each figure, "A-phase pulse" indicates the voltage pulse of the A-phase detection coil 112, "B-phase pulse" indicates the voltage pulse of the B-phase detection coil 113, and "C-phase pulse" indicates the voltage pulse of the C-phase detection coil 114.
図5(a)には、磁石111がCW方向に1回転したとき、すなわち、磁石基準の位置が0°(原点位置)から360°まで変化したときのA相パルス、B相パルスおよびC相パルスの波形が示されている。なお、図2の例では、A相検出コイル112は60°の位置に配置され、B相検出コイル113は原点位置(0°)に配置され、C相検出コイル114は300°の位置に配置されている。
FIG. 5(a) shows the waveforms of the A-phase pulse, B-phase pulse, and C-phase pulse when the magnet 111 rotates once in the CW direction, that is, when the magnet reference position changes from 0° (origin position) to 360°. In the example of FIG. 2, the A-phase detection coil 112 is arranged at a position of 60°, the B-phase detection coil 113 is arranged at the origin position (0°), and the C-phase detection coil 114 is arranged at a position of 300°.
図4で説明したように、検出コイル112,113,114の各々は、磁石111の回転周期の半周期ごとに正または負の電圧パルスを発生する。ただし、各電圧パルスの発生位置は、対応する検出コイルの配置位置ではなく、当該配置位置から角度φ/2だけずれた位置となる。例えば、正のA相パルスの発生位置は、A相検出コイル112の配置位置60°に対してCW方向にφ/2だけずれている。また、負のA相パルスの発生位置は、A相検出コイル112の配置位置60°と対称の位置240°に対してCW方向にφ/2だけずれている。これは、図3に示したように、磁石111による外部磁界が反転した後、外部磁界がある一定の強度(以下、閾値とも称する)に達しないと、磁性ワイヤの磁化Mの反転が生じないためである。このように磁石111の回転方向がCW方向の場合には、各電圧パルスの発生位置は、対応する検出コイルの配置位置からCW方向にずれた位置となる。
As described in FIG. 4, each of the detection coils 112, 113, 114 generates a positive or negative voltage pulse every half cycle of the magnet 111's rotation cycle. However, the position at which each voltage pulse is generated is not the arrangement position of the corresponding detection coil, but is shifted from the arrangement position by an angle of φ/2. For example, the position where the positive A-phase pulse is generated is shifted by φ/2 in the CW direction with respect to the arrangement position of the A-phase detection coil 112 of 60°. Also, the position where the negative A-phase pulse is generated is shifted by φ/2 in the CW direction with respect to the position 240° which is symmetrical with the arrangement position 60° of the A-phase detection coil 112 . This is because, as shown in FIG. 3, after the external magnetic field by the magnet 111 is reversed, the magnetization M of the magnetic wire is not reversed unless the external magnetic field reaches a certain strength (hereinafter also referred to as a threshold value). When the rotation direction of the magnet 111 is the CW direction in this manner, the position where each voltage pulse is generated is shifted in the CW direction from the arrangement position of the corresponding detection coil.
図5(b)には、磁石111がCCW方向に1回転したとき、すなわち、磁石基準の位置が360°から0°(原点位置)まで変化したときのA相パルス、B相パルスおよびC相パルスの波形が示されている。
FIG. 5(b) shows the waveforms of the A-phase pulse, B-phase pulse, and C-phase pulse when the magnet 111 rotates once in the CCW direction, that is, when the magnet reference position changes from 360° to 0° (origin position).
図5(b)においても、図5(a)と同様に、A相パルス、B相パルスおよびC相パルスの各々の発生位置は、対応する検出コイルの配置位置ではなく、当該配置位置から角度φ/2だけずれた位置となる。ただし、磁石111の回転方向がCCW方向の場合には、電圧パルスの発生位置は、対応する検出コイルの配置位置からCCW方向にずれた位置となる。
Also in FIG. 5(b), as in FIG. 5(a), the generation positions of the A-phase, B-phase, and C-phase pulses are not the arrangement positions of the corresponding detection coils, but positions shifted by an angle of φ/2 from the arrangement positions. However, when the rotation direction of the magnet 111 is the CCW direction, the position where the voltage pulse is generated is shifted in the CCW direction from the arrangement position of the corresponding detection coil.
以上に述べたように、A相検出コイル112,B相検出コイル113およびC相検出コイル114の各々は、磁石111の回転に応じて正および負の電圧パルスを発生する。回転検出機構110は、各相検出コイルから出力される電圧パルスを信号処理回路120に伝送する。信号処理回路120は、回転検出機構110から伝送される電圧パルスの電力を利用して信号処理回路120の電源電圧を生成する。また、信号処理回路120は、当該電圧パルスに基づいて回転軸115の回転方向および回転数を検出する。
As described above, each of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114 generates positive and negative voltage pulses according to the rotation of the magnet 111. The rotation detection mechanism 110 transmits voltage pulses output from each phase detection coil to the signal processing circuit 120 . The signal processing circuit 120 uses the power of the voltage pulse transmitted from the rotation detection mechanism 110 to generate a power supply voltage for the signal processing circuit 120 . Also, the signal processing circuit 120 detects the rotation direction and rotation speed of the rotating shaft 115 based on the voltage pulse.
ここで、回転軸115の回転数を検出するためには、まず、A相検出コイル112、B相検出コイル113およびC相検出コイル114の状態を示す状態信号を生成する必要がある。各相検出コイルの状態信号は、各相検出コイルが発生する電圧パルスに基づいて生成することができる。
Here, in order to detect the number of rotations of the rotating shaft 115, first, it is necessary to generate state signals indicating the states of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114. The state signal of each phase detection coil can be generated based on the voltage pulse generated by each phase detection coil.
具体的には、各相検出コイルの状態信号は、正の電圧パルスを発生したときにL(論理ロー)レベルからH(論理ハイ)レベルに立ち上がり、かつ、負の電圧パルスを発生したときにHレベルからLレベルに立ち下がるように生成することができる。すなわち、各相検出コイルの状態信号は、対応する検出コイルが正の電圧パルスを発生してから負の電圧パルスを発生するまでの間Hレベルに保持され、負の電圧パルスを発生してから正の電圧を発生するまでの間Lレベルに保持されることとなる。これによると、各相検出コイルの状態信号は、対応する検出コイルが発生した最後の電圧パルスの極性を表す信号となる。
Specifically, the state signal of each phase detection coil can be generated so that it rises from L (logic low) level to H (logic high) level when a positive voltage pulse is generated, and falls from H level to L level when a negative voltage pulse is generated. That is, the state signal of each phase detection coil is held at H level from the generation of the positive voltage pulse until the corresponding detection coil generates the negative voltage pulse, and is held at the L level from generation of the negative voltage pulse until generation of the positive voltage. According to this, the state signal of each phase detection coil becomes a signal representing the polarity of the last voltage pulse generated by the corresponding detection coil.
図6は、磁石111が回転している場合のA相検出コイル112、B相検出コイル113およびC相検出コイル114の状態信号の変化を示す図である。図6(a)は磁石111がCW方向に回転しているときの各相検出コイルの状態信号の変化を示し、図6(b)は磁石111がCCW方向に回転しているときの各相検出コイルの状態信号の変化を示している。図6(a)および図6(b)に示すように、何れの状態信号も180°(半周期)ごとにHレベルとLレベルとの間で交互に変化する。
FIG. 6 is a diagram showing changes in state signals of the A-phase detection coil 112, the B-phase detection coil 113, and the C-phase detection coil 114 when the magnet 111 is rotating. 6A shows changes in the state signals of the phase detection coils when the magnet 111 rotates in the CW direction, and FIG. 6B shows changes in the state signals of the phase detection coils when the magnet 111 rotates in the CCW direction. As shown in FIGS. 6(a) and 6(b), both state signals alternately change between H level and L level every 180° (half cycle).
ここで、図2に示した「原点位置」付近で回転数データを変化させる場合(すなわち、回転数をカウントする場合)を考える。具体的には、磁石基準が原点位置にある状態(図2)から磁石111がCW方向に回転し、再び磁石基準が原点位置を通過したときに、回転数(カウント値)を+1増加(カウントアップ)させることとする。また、磁石基準が原点位置にある状態から磁石111がCCW方向に回転し、再び磁石基準が原点位置を通過したときに、回転数(カウント値)を-1減少(カウントダウン)させることとする。
Here, consider the case of changing the number of revolutions data near the "origin position" shown in FIG. 2 (that is, counting the number of revolutions). Specifically, when the magnet 111 rotates in the CW direction from the state where the magnet reference is at the origin position (FIG. 2) and the magnet reference passes the origin position again, the number of rotations (count value) is increased by +1 (counted up). Also, when the magnet 111 rotates in the CCW direction from the state where the magnet reference is at the origin position and the magnet reference passes the origin position again, the number of revolutions (count value) is decreased by -1 (counted down).
この場合、図6(a)によると、A相検出コイル112の状態信号がHレベルであって、B相検出コイル113の状態信号がHレベルからLレベルに立ち下がったことが検出されたときには、磁石基準が原点位置をCW方向に通過したものと判断されるため、回転数を+1増加させる。また、図6(b)によると、A相検出コイル112の状態信号がHレベルであって、B相検出コイル113の状態信号がLレベルからHレベルに立ち上がったことが検出されたときには、磁石基準が原点位置をCCW方向に通過したものと判断されるため、回転数を-1減少させる。
In this case, according to FIG. 6(a), when it is detected that the state signal of the A-phase detection coil 112 is H level and the state signal of the B-phase detection coil 113 has fallen from H level to L level, it is determined that the magnet reference has passed the origin position in the CW direction, so the rotation speed is increased by +1. Further, according to FIG. 6(b), when it is detected that the state signal of the A-phase detection coil 112 is at H level and the state signal of the B-phase detection coil 113 rises from L level to H level, it is determined that the magnet reference has passed the origin position in the CCW direction, so the rotation speed is decreased by -1.
あるいは、C相検出コイル114の状態信号がLレベルであって、B相検出コイル113の状態信号の立ち下がりが検出されたときには回転数を+1増加させ、C相検出コイル114の状態信号がLレベルであって、B相検出コイル113の状態信号の立ち上がりが検出されたときには回転数を-1減少させる構成とすることができる。
Alternatively, when the state signal of the C-phase detection coil 114 is at L level and the fall of the state signal of the B-phase detection coil 113 is detected, the rotation speed is increased by +1, and when the state signal of the C-phase detection coil 114 is at L level and the rise of the state signal of the B-phase detection coil 113 is detected, the rotation speed is decreased by -1.
あるいは、A相検出コイル112の状態信号がHレベルであり、C相検出コイル114の状態信号がLレベルであり、かつ、B相検出コイル113の状態信号の立ち下がりが検出されたときには回転数を+1増加させ、A相検出コイル112の状態信号がHレベルであり、C相検出コイル114の状態信号がLレベルであり、かつ、B相検出コイル113の状態信号の立ち上がりが検出されたときには回転数を-1減少させる構成とすることができる。
Alternatively, when the state signal of the A phase detection coil 112 is at H level, the state signal of the C phase detection coil 114 is at L level, and the fall of the state signal of the B phase detection coil 113 is detected, the rotation speed is increased by +1, and when the state signal of the A phase detection coil 112 is at H level, the state signal of the C phase detection coil 114 is at L level, and the rise of the state signal of the B phase detection coil 113 is detected, the rotation speed is decreased by -1. can be configured.
さらに、各相検出コイルの状態信号を見ることによって、磁石基準がどの領域に位置するのか、すなわち、磁石111の回転位置を推定することが可能となる。例えば、A相検出コイル112の状態信号がHレベルであり、B相検出コイル113の状態信号がLレベルであり、C相検出コイル114の状態信号がLレベルであるときには、磁石基準が領域1に位置していると推定することができる。これによると、磁石基準が領域6から領域1に移動したときには磁石111がCW方向に1回転したと判断して、回転数を+1増加させ、磁石基準が領域1から領域6に移動したときには磁石111がCCW方向に1回転したと判断して、回転数を-1減少させることができる。
Furthermore, by looking at the state signal of each phase detection coil, it is possible to estimate in which region the magnet reference is located, that is, the rotational position of the magnet 111 . For example, when the state signal of the A-phase detection coil 112 is at H level, the state signal of the B-phase detection coil 113 is at L level, and the state signal of the C-phase detection coil 114 is at L level, it can be estimated that the magnet reference is located in region 1. According to this, when the magnet reference moves from region 6 to region 1, it is determined that the magnet 111 has made one rotation in the CW direction, and the number of rotations is increased by +1.
(信号処理回路の構成)
次に、図1に示した信号処理回路120の構成および動作について説明する。 (Configuration of signal processing circuit)
Next, the configuration and operation ofsignal processing circuit 120 shown in FIG. 1 will be described.
次に、図1に示した信号処理回路120の構成および動作について説明する。 (Configuration of signal processing circuit)
Next, the configuration and operation of
図7は、信号処理回路120のハードウェア構成を示す図である。図7に示すように、信号処理回路120は、CPU(Central Processing Unit)10と、RAM(Random Access Memory)11と、ROM(Read Only Memory)12と、I/F(Interface)装置13と、記憶装置14とを含む。CPU10、RAM11、ROM12、I/F装置13および記憶装置14は、通信バス15を通じて各種データを遣り取りする。
FIG. 7 is a diagram showing the hardware configuration of the signal processing circuit 120. As shown in FIG. As shown in FIG. 7, the signal processing circuit 120 includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 11, a ROM (Read Only Memory) 12, an I/F (Interface) device 13, and a storage device 14. CPU 10 , RAM 11 , ROM 12 , I/F device 13 and storage device 14 exchange various data through communication bus 15 .
CPU10は、ROM12に格納されているプログラムをRAM11に展開して実行する。ROM12に格納されているプログラムには、信号処理回路120によって実行される処理が記述されている。
The CPU 10 expands the program stored in the ROM 12 to the RAM 11 and executes it. A program stored in the ROM 12 describes processing to be executed by the signal processing circuit 120 .
I/F装置13は、回転検出機構110および外部機器と信号およびデータを遣り取りするための入出力装置である。I/F装置13は、回転検出機構110から検出コイル112,113,114が出力した電圧パルスを受信する。
The I/F device 13 is an input/output device for exchanging signals and data with the rotation detection mechanism 110 and external devices. The I/F device 13 receives voltage pulses output by the detection coils 112 , 113 and 114 from the rotation detection mechanism 110 .
記憶装置14は、各種情報を記憶するストレージであって、回転検出機構110の情報、回転体の情報等を記憶する。また、記憶装置14は、回転検出機構110から受信した電圧パルスから取得される情報(検出コイルの状態、回転軸115の回転数等)を記憶するための、更新可能な不揮発性メモリを有している。不揮発性メモリについては、後ほど詳しく説明する。
The storage device 14 is a storage that stores various types of information, such as information on the rotation detection mechanism 110 and information on the rotating body. The storage device 14 also has an updatable non-volatile memory for storing information obtained from the voltage pulse received from the rotation detection mechanism 110 (the state of the detection coil, the number of rotations of the rotary shaft 115, etc.). The non-volatile memory will be explained in detail later.
なお、CPU10がプログラムを実行することで実現される機能の全部または一部を、集積回路などのハードワイヤード回路(hard-wired circuit)を用いて実現してもよい。例えば、ASIC(Application Specific Integrated Circuit)、FPGA(Field-Programmable Gate Array)またはCPLD(Complex Programmable Logic Device)などを用いて実現してもよい。
All or part of the functions realized by the CPU 10 executing the program may be realized using a hard-wired circuit such as an integrated circuit. For example, it may be realized using ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), or CPLD (Complex Programmable Logic Device).
図1に戻って、信号処理回路120の機能構成を説明する。信号処理回路120は、全波整流回路121_A,121_B,121_Cと、定電圧回路122と、Enable(イネーブル)回路123と、パルス波形符号判定回路124と、コントローラ125と、アダー126と、不揮発性メモリ127と、外部回路I/F128と、電源切替回路129とを含む。このうちの少なくともコントローラ125およびアダー126は、図7に示すCPU10(図7参照)がプログラムを実行することによって実現される。
Returning to FIG. 1, the functional configuration of the signal processing circuit 120 will be described. The signal processing circuit 120 includes full-wave rectifier circuits 121_A, 121_B, 121_C, a constant voltage circuit 122, an enable circuit 123, a pulse waveform sign determination circuit 124, a controller 125, an adder 126, a nonvolatile memory 127, an external circuit I/F 128, and a power supply switching circuit 129. Of these, at least the controller 125 and the adder 126 are implemented by the CPU 10 (see FIG. 7) shown in FIG. 7 executing programs.
信号処理回路120は、回転検出機構110にて検出コイル112,113,114の何れかが電圧パルスを出力する毎に、以下に述べる一連の動作を実行する。
The signal processing circuit 120 executes the series of operations described below each time one of the detection coils 112, 113, and 114 in the rotation detection mechanism 110 outputs a voltage pulse.
全波整流回路121_Aは、A相検出コイル112と電気的に接続されており、A相検出コイル112から出力される電圧パルス(A相パルス)を全波整流し、整流された電圧パルスを定電圧回路122へ出力する。
The full-wave rectifier circuit 121_A is electrically connected to the A-phase detection coil 112, full-wave rectifies the voltage pulse (A-phase pulse) output from the A-phase detection coil 112, and outputs the rectified voltage pulse to the constant voltage circuit 122.
全波整流回路121_Bは、B相検出コイル113と電気的に接続されており、B相検出コイル113から出力される電圧パルス(B相パルス)を全波整流し、整流された電圧パルスを定電圧回路122へ出力する。
The full-wave rectifier circuit 121_B is electrically connected to the B-phase detection coil 113, full-wave rectifies the voltage pulse (B-phase pulse) output from the B-phase detection coil 113, and outputs the rectified voltage pulse to the constant voltage circuit 122.
全波整流回路121_Cは、C相検出コイル114と電気的に接続されており、C相検出コイル114から出力される電圧パルス(C相パルス)を全波整流し、整流された電圧パルスを定電圧回路122へ出力する。
The full-wave rectifier circuit 121_C is electrically connected to the C-phase detection coil 114, full-wave rectifies the voltage pulse (C-phase pulse) output from the C-phase detection coil 114, and outputs the rectified voltage pulse to the constant voltage circuit 122.
定電圧回路122は、全波整流回路121_A,121_B,121_Cのうちの何れかから与えられる電圧パルスから一定電圧を生成し、生成した一定電圧を電源電圧としてEnable回路123、パルス波形符号判定回路124、コントローラ125、アダー126、および不揮発性メモリ127へ供給する。
The constant voltage circuit 122 generates a constant voltage from the voltage pulse given from one of the full-wave rectifier circuits 121_A, 121_B, and 121_C, and supplies the generated constant voltage as a power supply voltage to the enable circuit 123, the pulse waveform sign determination circuit 124, the controller 125, the adder 126, and the nonvolatile memory 127.
なお、電源切替回路129は、コントローラ125および不揮発性メモリ127に対する電力の供給源を、定電圧回路122と回転検出器101の外部に設けられた図示しない外部電源との間で切り替え可能に構成される。外部電源は回転体を駆動するための主電源である。これによると、コントローラ125および不揮発性メモリ127に対しては、回転軸115の停止中においても電力を供給し続けることができる。
The power supply switching circuit 129 is configured to switch the power supply source for the controller 125 and the nonvolatile memory 127 between the constant voltage circuit 122 and an external power supply (not shown) provided outside the rotation detector 101 . The external power supply is the main power supply for driving the rotating body. According to this, power can be continuously supplied to the controller 125 and the nonvolatile memory 127 even while the rotation shaft 115 is stopped.
不揮発性メモリ127は、電圧パルスが生じたときの各相検出コイルの状態、回転軸115の回転数、および、電圧パルスを発生した検出コイルの情報(検出コイル番号)を記憶する。これらの情報は、検出コイル112,113,114の何れかが電圧パルスを発生する毎に取得されて不揮発性メモリ127に記憶される。不揮発性メモリ127はさらに、後述する変換テーブル(図8および図9参照)を記憶する。
The non-volatile memory 127 stores the state of each phase detection coil when the voltage pulse is generated, the rotation speed of the rotating shaft 115, and the information (detection coil number) of the detection coil that generated the voltage pulse. These pieces of information are acquired and stored in the non-volatile memory 127 each time one of the detection coils 112, 113, and 114 generates a voltage pulse. Nonvolatile memory 127 further stores a conversion table (see FIGS. 8 and 9), which will be described later.
なお、不揮発性メモリ127は、各相検出コイルの状態、および電圧パルスを発生した検出コイルの情報については、少なくとも、前回の電圧パルスが生じたときの各相検出コイルの状態および前回の電圧パルスを発生した検出コイルの情報、ならびに、前々回の電圧パルスが生じたときの各相検出コイルの状態および前々回の電圧パルスを出力した検出コイルの情報を保持するように構成される。これらの情報は、電圧パルスが発生する毎にコントローラ125によって更新される。
Note that the nonvolatile memory 127 is configured to hold at least the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that generated the previous voltage pulse, and the state of each phase detection coil when the voltage pulse before the previous time was generated and the information about the detection coil that output the voltage pulse before the previous time, with respect to the state of each phase detection coil and the information about the detection coil that generated the voltage pulse. These information are updated by controller 125 each time a voltage pulse occurs.
Enable回路123は、定電圧回路122から供給される電圧が安定したことが確認されると、パルス波形符号判定回路124、コントローラ125、アダー126、および不揮発性メモリ127に対し、動作を開始させるためのトリガ信号を送信する。
When the enable circuit 123 confirms that the voltage supplied from the constant voltage circuit 122 has stabilized, the enable circuit 123 sends a trigger signal for starting operation to the pulse waveform sign determination circuit 124, controller 125, adder 126, and nonvolatile memory 127.
パルス波形符号判定回路124は、Enable回路123からトリガ信号を受けて動作を開始する。パルス波形符号判定回路124は、A相検出コイル112から出力される電圧パルス(A相パルス)に基づいてA相検出コイル112の検出信号を生成し、B相検出コイル113から出力される電圧パルス(B相パルス)に基づいてB相検出コイル113の検出信号を生成し、C相検出コイル114から出力される電圧パルス(C相パルス)に基づいてC相検出コイル114の検出信号を生成する。
The pulse waveform sign determination circuit 124 receives a trigger signal from the enable circuit 123 and starts operating. The pulse waveform sign determination circuit 124 generates a detection signal for the A-phase detection coil 112 based on the voltage pulse (A-phase pulse) output from the A-phase detection coil 112, generates a detection signal for the B-phase detection coil 113 based on the voltage pulse (B-phase pulse) output from the B-phase detection coil 113, and generates a detection signal for the C-phase detection coil 114 based on the voltage pulse (C-phase pulse) output from the C-phase detection coil 114.
各相検出コイルの検出信号は、各相検出コイルからの電圧パルスの発生の有無、および、発生した電圧パルスの極性を示す信号である。検出信号は、対応する検出コイルが正の電圧パルスを発生したときにHレベルとなり、負の電圧パルスを発生したときにLレベルとなり、電圧パルスを発生していないときには0となる。すなわち、検出信号は、各相検出コイルが発生する電圧パルスの情報を履歴として残すものである。パルス波形符号判定回路124は、生成した検出信号をコントローラ125に送信する。
The detection signal of each phase detection coil is a signal that indicates whether or not a voltage pulse is generated from each phase detection coil and the polarity of the generated voltage pulse. The detection signal becomes H level when the corresponding detection coil generates a positive voltage pulse, becomes L level when it generates a negative voltage pulse, and becomes 0 when no voltage pulse is generated. That is, the detection signal leaves information of voltage pulses generated by each phase detection coil as a history. The pulse waveform sign determination circuit 124 transmits the generated detection signal to the controller 125 .
コントローラ125は、パルス波形符号判定回路124から受信した各相検出コイルの検出信号をアダー126へ送信する。コントローラ125は、さらに、不揮発性メモリ127にアクセスすることにより、前回の電圧パルスが生じたときの回転軸115の回転数と、前回の電圧パルスが生じたときの各相検出コイルの状態および当該電圧パルスを発生した検出コイルの情報と、前々回の電圧パルスが生じたときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報とを不揮発性メモリ127から読み出す。コントローラ125は、読み出したこれらの情報をアダー126へ送信する。
The controller 125 transmits the detection signal of each phase detection coil received from the pulse waveform sign determination circuit 124 to the adder 126 . The controller 125 further accesses the nonvolatile memory 127 to read out from the nonvolatile memory 127 the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that generated the voltage pulse, and the state of each phase detection coil when the voltage pulse was generated the last time before and the information about the detection coil that output the voltage pulse. The controller 125 transmits the read information to the adder 126 .
アダー126は、コントローラ125から受信した情報(今回の電圧パルスが生じたときの各相検出コイルの状態信号、および不揮発性メモリ127から読み出した情報)に基づいて、後述する変換テーブル(図8および図9参照)を用いて、各相検出コイルの状態および回転数を、最新の各相検出コイルの状態および回転数にそれぞれ更新する。アダー126は、更新された最新の各相検出コイルの状態および回転数をコントローラ125に送信する。
The adder 126 updates the state and rotation speed of each phase detection coil to the latest state and rotation speed of each phase detection coil using a conversion table (see FIGS. 8 and 9), which will be described later, based on the information received from the controller 125 (the state signal of each phase detection coil when the current voltage pulse is generated and the information read from the nonvolatile memory 127). The adder 126 transmits to the controller 125 the latest updated state and rotation speed of each phase detection coil.
コントローラ125は、アダー126からの情報を受信すると、再び不揮発性メモリ127にアクセスし、最新の各相検出コイルの状態および回転数と、今回の電圧パルスを発生した検出コイルの情報とを不揮発性メモリ127に書き込む。
When the controller 125 receives the information from the adder 126, it accesses the non-volatile memory 127 again and writes the latest state and rotation speed of each phase detection coil and the information of the detection coil that generated the current voltage pulse into the non-volatile memory 127.
信号処理回路120は、上述した一連の動作を、検出コイル112,113,114の何れかが電圧パルスを出力する毎に、当該電圧パルスから生成される電源電圧を用いて実行することにより、信号処理回路120は、バッテリレスで回転軸115の回転数を検出することができる。
The signal processing circuit 120 executes the above-described series of operations using the power supply voltage generated from the voltage pulse each time one of the detection coils 112, 113, and 114 outputs a voltage pulse, thereby enabling the signal processing circuit 120 to detect the rotation speed of the rotating shaft 115 without a battery.
なお、回転検出器101の外部から回転軸115の回転数を読み取る場合には、外部回路I/F128およびコントローラ125を経由して不揮発性メモリ127にアクセスすることにより、回転数を読み取ることができる。このとき、上述した回転数更新のための一連動作を、外部からの回転数の読み取り動作とバッティングしないように、コントローラ125は、外部から不揮発性メモリ127へのアクセスを制限するように構成される。
When reading the number of rotations of the rotating shaft 115 from the outside of the rotation detector 101, the number of rotations can be read by accessing the nonvolatile memory 127 via the external circuit I/F 128 and the controller 125. At this time, the controller 125 is configured to restrict access to the nonvolatile memory 127 from the outside so that the series of operations for updating the rotation speed described above do not conflict with the reading operation of the rotation speed from the outside.
また、外部から不揮発性メモリ127にアクセスする場合には、電源切替回路129は、外部電源(主電源)からコントローラ125および不揮発性メモリ127へ電源電圧を供給する。さらに、外部回路I/F128に対して外部電源から直接に電源電圧を供給する。したがって、電圧パルスの電力に依らずに、回転数を読み取ることができる。
When accessing the nonvolatile memory 127 from the outside, the power supply switching circuit 129 supplies power supply voltage from the external power supply (main power supply) to the controller 125 and the nonvolatile memory 127 . Further, the power supply voltage is directly supplied from the external power supply to the external circuit I/F 128 . Therefore, the rotation speed can be read without depending on the power of the voltage pulse.
これにより、外部電源からの電力供給時には、信号処理回路120に内蔵されるレジスタ(図示せず)に不揮発性メモリ127に記憶される情報を呼び出しておき、電力供給が終了したことが検知された時点で、レジスタから不揮発性メモリ127に情報を格納する構成とすることにより、不揮発性メモリ127へのアクセスがバッティングすることを回避することが可能となる。
As a result, when power is supplied from an external power source, information stored in the non-volatile memory 127 is called to a register (not shown) built into the signal processing circuit 120, and when it is detected that the power supply has ended, the information is stored from the register to the non-volatile memory 127, thereby making it possible to avoid conflicting accesses to the non-volatile memory 127.
(更新処理)
上述したように、アダー126は、磁石111の回転に応じて検出コイル112,113,114の各々から出力される電圧パルスに基づいて、不揮発性メモリ127に記憶される各相検出コイルの状態および回転軸115の回転数を更新する処理を実行する。ただし、磁石111の回転中、少なくとも1つの検出コイルにおいて電圧パルスが欠落する現象(以下、「パルス抜け」とも称する)が発生した場合には、アダー126は、更新処理の際に、欠落した電圧パルスを補うための補正処理を実行するように構成される。この補正を含む更新処理は、図8および図9に示す変換テーブルに従って実行される。 (Update processing)
As described above,adder 126 updates the state of each phase detection coil stored in nonvolatile memory 127 and the number of rotations of rotating shaft 115 based on the voltage pulses output from each of detection coils 112, 113, and 114 in accordance with the rotation of magnet 111. However, when a phenomenon in which a voltage pulse is missing in at least one detection coil (hereinafter also referred to as “pulse missing”) occurs during rotation of the magnet 111, the adder 126 is configured to perform correction processing to compensate for the missing voltage pulse during update processing. The update process including this correction is executed according to the conversion tables shown in FIGS. 8 and 9. FIG.
上述したように、アダー126は、磁石111の回転に応じて検出コイル112,113,114の各々から出力される電圧パルスに基づいて、不揮発性メモリ127に記憶される各相検出コイルの状態および回転軸115の回転数を更新する処理を実行する。ただし、磁石111の回転中、少なくとも1つの検出コイルにおいて電圧パルスが欠落する現象(以下、「パルス抜け」とも称する)が発生した場合には、アダー126は、更新処理の際に、欠落した電圧パルスを補うための補正処理を実行するように構成される。この補正を含む更新処理は、図8および図9に示す変換テーブルに従って実行される。 (Update processing)
As described above,
図8および図9に示す変換テーブルは、磁石111の回転に伴う各相検出コイルの状態および磁石基準が位置する領域の遷移を表している。この変換テーブルにおいて、「現在のステータス」は、前回の電圧パルスが生じてから今回の電圧パルスが生じるまでの各相検出コイルの状態、および当該各相検出コイルの状態から推定される磁石基準が位置する領域を示している。
The conversion tables shown in FIGS. 8 and 9 represent the transition of the state of each phase detection coil and the region where the magnet reference is located as the magnet 111 rotates. In this conversion table, "current status" indicates the state of each phase detection coil from the previous voltage pulse to the current voltage pulse, and the region where the magnet reference estimated from the state of each phase detection coil is located.
「前回のステータス」は、前々回の電圧パルスが生じてから前回の電圧パルスが生じるまでの各相検出コイルの状態、および当該各相検出コイルの状態から推定される磁石基準が位置する領域を示している。なお、現在のステータスおよび前回のステータスの各々は、今回の電圧パルスが生じたことに応じて更新される。
"Previous status" indicates the state of each phase detection coil from the generation of the voltage pulse before the previous to the generation of the previous voltage pulse, and the region where the magnet reference estimated from the state of each phase detection coil is located. Note that each of the current status and the previous status are updated in response to the occurrence of the current voltage pulse.
また、変換テーブルにおいて、「更新前」とは、今回の電圧パルスによって状態が更新される前を意味し、「更新後」とは、今回の電圧パルスによって状態が更新された後を意味する。更新前の情報には、「現在のステータス」および「前回のステータス」に加えて、前々回の電圧パルスを発生した検出コイルの情報(「前々回検出コイル番号」と表記)が含まれている。
Also, in the conversion table, "before update" means before the state is updated by this voltage pulse, and "after update" means after the state is updated by this voltage pulse. The information before updating includes information on the detection coil that generated the voltage pulse two times before (denoted as "detection coil number two times before") in addition to the "current status" and "previous status".
更新後の情報には、「現在のステータス」および「前回のステータス」に加えて、回転軸115の回転数のカウント値の補正量(「カウント」と表記)が含まれている。なお、値「0」は回転数を補正しないことを示し、値「1」は回転数を+1増加させることを示し、値「-1」は回転数を-1減少させることを示す。
The updated information includes the "current status" and "previous status" as well as the correction amount of the count value of the number of revolutions of the rotating shaft 115 (denoted as "count"). The value "0" indicates that the number of rotations is not corrected, the value "1" indicates that the number of rotations is increased by +1, and the value "-1" indicates that the number of rotations is decreased by -1.
変換テーブルには、さらに、検出コイル112,113,114の各々の検出信号(「発電素子入力」と表記)が示されている。この検出信号は、上述したパルス波形符号判定回路124(図1)にて生成される信号である。「H」は検出コイルが正の電圧パルスを発生したことを示し、「L」は検出コイルが負の電圧パルスを発生したことを示し、「0」は検出コイルが電圧パルスを発生していないことを示す。なお、検出信号を不揮発性メモリ127に保持する場合には、「0」、「H」、「L」に代えて、検出信号をエンコードすることによって情報を圧縮してもよい。
The conversion table further shows the detection signal of each of the detection coils 112, 113, and 114 (denoted as "power generation element input"). This detection signal is a signal generated by the above-described pulse waveform code determination circuit 124 (FIG. 1). A "H" indicates that the sensing coil generated a positive voltage pulse, an "L" indicates that the sensing coil generated a negative voltage pulse, and a "0" indicates that the sensing coil did not generate a voltage pulse. When the detection signal is stored in the non-volatile memory 127, information may be compressed by encoding the detection signal instead of "0", "H", and "L".
信号処理回路120は、変換テーブルに表示されていない状態遷移が現れた場合には、想定されるパルス抜けとは異なる現象が発生していると判断して、エラーを出力する。
When a state transition that is not displayed in the conversion table appears, the signal processing circuit 120 determines that a phenomenon different from the expected missing pulse has occurred, and outputs an error.
以下に、アダー126により実行される補正処理を含む更新処理について説明する。
ここで、「パルス抜け」には、磁石111の回転方向が反転した直後のタイミングで生じるパルス抜けと、上記タイミング以外のタイミングで生じるパルス抜けとが存在する。アダー126は、これら2種類のパルス抜けの各々に対して補正処理を実行する。 Update processing including correction processing executed by theadder 126 will be described below.
Here, the "missing pulse" includes a missing pulse that occurs immediately after the rotation direction of themagnet 111 is reversed and a missing pulse that occurs at a timing other than the above timing. The adder 126 performs correction processing for each of these two types of missing pulses.
ここで、「パルス抜け」には、磁石111の回転方向が反転した直後のタイミングで生じるパルス抜けと、上記タイミング以外のタイミングで生じるパルス抜けとが存在する。アダー126は、これら2種類のパルス抜けの各々に対して補正処理を実行する。 Update processing including correction processing executed by the
Here, the "missing pulse" includes a missing pulse that occurs immediately after the rotation direction of the
最初に、回転軸115の回転方向が反転した直後のタイミングで生じるパルス抜けに対する補正処理について説明する。
First, the correction processing for missing pulses occurring immediately after the rotation direction of the rotating shaft 115 is reversed will be described.
検出コイルから電圧パルスを発生させた直後に磁石111の回転方向が反転した場合には、磁石111の反転によって上記電圧パルスを発生させた磁界とは逆極性の磁界が検出コイルに印加される。この印加される磁界の強度が閾値を上回ったときであっても、検出コイルから発生する電圧パルスの電圧レベルが小さくなるという現象が起きることがある。電圧パルスの電圧レベルの低下が著しい場合には、信号処理回路120は、電圧パルスの電力を受けて動作することができず、パルス抜けが発生する。その結果、実際の磁石基準の位置と、不揮発性メモリ127に保持されている各相検出コイルの状態から推定される磁石基準の位置とが一致しない現象が発生してしまう。
When the direction of rotation of the magnet 111 is reversed immediately after the voltage pulse is generated from the detection coil, the reversal of the magnet 111 applies a magnetic field of opposite polarity to the magnetic field that generated the voltage pulse to the detection coil. Even when the intensity of the applied magnetic field exceeds the threshold, a phenomenon may occur in which the voltage level of the voltage pulse generated from the detection coil becomes small. When the voltage level of the voltage pulse drops significantly, the signal processing circuit 120 cannot receive the power of the voltage pulse to operate, and a missing pulse occurs. As a result, a phenomenon occurs in which the actual magnet reference position does not match the magnet reference position estimated from the state of each phase detection coil held in the nonvolatile memory 127 .
ここで、「第1の例」として、原点位置にB相検出コイル113が配置され、磁石基準が原点位置にある状況(図2参照)から、磁石基準がCW方向に領域6から領域1へ移動し、B相検出コイル112に印加される磁界の強度が閾値を超えた場合を想定する。これにより、B相検出コイル112から電圧パルスが発生する。その後、電圧パルスの発生直後に磁石111の回転がCCW方向に反転したことによって、磁石基準が領域1から領域6に戻ったものとする。
Here, as a "first example", assume that the B-phase detection coil 113 is placed at the origin position and the magnet reference is at the origin position (see FIG. 2), the magnet reference moves in the CW direction from region 6 to region 1, and the strength of the magnetic field applied to the B-phase detection coil 112 exceeds the threshold. Thereby, a voltage pulse is generated from the B-phase detection coil 112 . After that, it is assumed that the magnet reference returns from the region 1 to the region 6 due to the rotation of the magnet 111 being reversed in the CCW direction immediately after the generation of the voltage pulse.
このとき、回転検出器101において、磁石111がCCW方向に回転することにより、B相検出コイル113に印加される逆極性の磁界の強度が閾値を超える。しかしながら、B相検出コイル113が発生する電圧パルスの電圧レベルが小さく、信号処理回路120が動作しないために、「パルス抜け」が発生する。その結果、コントローラ125は、不揮発性メモリ127に保持される各相検出コイルの状態および磁石基準の位置を更新することなく、磁石基準が領域1に位置することを示す各相検出コイルの状態を保持する。
At this time, in the rotation detector 101, the magnet 111 rotates in the CCW direction, so that the strength of the opposite polarity magnetic field applied to the B-phase detection coil 113 exceeds the threshold. However, since the voltage level of the voltage pulse generated by the B-phase detection coil 113 is small and the signal processing circuit 120 does not operate, "missing pulse" occurs. As a result, controller 125 retains the state of each phase detection coil indicating that the magnet reference is located in region 1 without updating the state of each phase detection coil and the position of the magnet reference held in non-volatile memory 127 .
磁石111がCCW方向にさらに回転を続けると、C相検出コイル114に印加される磁界の強度が閾値を超えることにより、C相検出コイル114が電圧パルスを発生する。しかしながら、上述のように、不揮発性メモリ127は、磁石基準が領域1に位置するときの各相検出コイルの状態を保持している。一方、磁石基準が領域1から領域6または領域2に移動したときに電圧パルスを発生するのはB相検出コイル113またはA相検出コイル112だけであり、C相検出コイル114ではないため、アダー126は、パルス抜けが発生したことを検知することができる。
When the magnet 111 continues to rotate in the CCW direction, the strength of the magnetic field applied to the C-phase detection coil 114 exceeds the threshold, causing the C-phase detection coil 114 to generate a voltage pulse. However, as described above, non-volatile memory 127 retains the state of each phase detection coil when the magnet reference is located in Region 1. FIG. On the other hand, only the B-phase detection coil 113 or the A-phase detection coil 112, and not the C-phase detection coil 114, generates a voltage pulse when the magnet reference moves from the region 1 to the region 6 or the region 2. Therefore, the adder 126 can detect that the missing pulse has occurred.
上記第1の例のように、磁石基準が領域1に位置するときの各相検出コイルの状態を保持しているときにC相検出コイル114が電圧パルスを発生するという状況は、磁石基準がCCW方向に領域2から領域1へ移動し、その直後に磁石111の回転方向が反転した場合にも発生し得る。この場合を「第2の例」と称する。
As in the first example above, the situation in which the C-phase detection coil 114 generates a voltage pulse while the state of each phase detection coil is maintained when the magnet reference is located in region 1 can also occur when the magnet reference moves in the CCW direction from region 2 to region 1 and immediately after that, the rotation direction of the magnet 111 reverses. This case is called a "second example".
第2の例では、磁石基準が領域1から領域2へ戻ったときに、A相検出コイル112のパルス抜けが発生し、さらに磁石111がCW方向に回転を続けることで、磁石基準が領域3に移動すると、C相検出コイル114が電圧パルスを発生する。第2の例においても、第1の例と同様に、磁石基準が領域1に位置する状態から、C相検出コイル114が電圧パルスを発生する領域への磁石基準の移動が存在しないため、アダー126は、パルス抜けが発生したことを検知することができる。
In the second example, when the magnet reference returns from region 1 to region 2, pulse missing occurs in the A-phase detection coil 112, and when the magnet 111 continues to rotate in the CW direction and the magnet reference moves to region 3, the C-phase detection coil 114 generates a voltage pulse. In the second example, as in the first example, since the magnet reference does not move from the state where the magnet reference is located in region 1 to the region where the C-phase detection coil 114 generates the voltage pulse, the adder 126 can detect the occurrence of the missing pulse.
ここで、第1の例と第2の例とは何れも、前回の電圧パルスを発生したときの各相検出コイルの状態から推定される磁石基準の位置が領域1であるため、第1の例と第2の例とを区別することができない。そのため、パルス抜けを検知することができても、磁石基準の位置および回転数を補正することができない。
Here, in both the first example and the second example, since the position of the magnet reference estimated from the state of each phase detection coil when the previous voltage pulse was generated is region 1, the first example and the second example cannot be distinguished. Therefore, even if the missing pulse can be detected, the magnet-based position and rotation speed cannot be corrected.
一方、不揮発性メモリ127に保持されている、前々回の電圧パルスを発生したときの各相検出コイルの状態から推定される磁石基準の位置は、第1の例が領域6であるのに対して第2の例が領域2であり、両者は異なっている。したがって、第1の例と第2の例とを区別することができる。具体的には、第1の例では、磁石基準が領域1から領域6に移動する際にパルス抜けが発生し、その後、磁石基準が領域6から領域5に移動する際にC相検出コイル114が電圧パルスを発生したものと推定することができる。したがって、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)について、磁石基準が領域1からCCW方向に1領域跳んだ領域5に位置するときの各相検出コイルの状態に補正するとともに、回転数を-1減らす補正をすることができる。図8の変換テーブルでは、この補正処理が「第1の例」で示されている。
On the other hand, the position of the magnet reference, which is held in the nonvolatile memory 127 and is estimated from the state of each phase detection coil when the voltage pulse was generated before the last time, is area 6 in the first example and area 2 in the second example, and both are different. Therefore, it is possible to distinguish between the first example and the second example. Specifically, in the first example, it can be estimated that the missing pulse occurs when the magnet reference moves from region 1 to region 6, and then the C-phase detection coil 114 generates a voltage pulse when the magnet reference moves from region 6 to region 5. Therefore, the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, can be corrected to the state of each phase detection coil when the magnet reference is located in region 5, which is one region jumped in the CCW direction from region 1, and the number of rotations can be reduced by -1. In the conversion table of FIG. 8, this correction processing is indicated by "first example".
第2の例においても、第1の例と同様に、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)および回転数を補正することができる。具体的には、第2の例では、磁石基準が領域1から領域2に移動する際にパルス抜けが発生し、その後、磁石基準が領域2から領域3に移動する際にC相検出コイル114が電圧パルスを発生したものと推定することができる。したがって、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)について、磁石基準が領域1からCW方向に1領域跳んだ領域3に位置するときの各相検出コイルの状態に補正することができる。ただし、第2の例では回転数の補正は行われない。図8の変換テーブルでは、この補正処理が「第2の例」で示されている。
Also in the second example, as in the first example, the state (current status) and rotation speed of each phase detection coil when the previous voltage pulse was generated, which are held in the nonvolatile memory 127, can be corrected. Specifically, in the second example, it can be estimated that the missing pulse occurs when the magnet reference moves from region 1 to region 2, and then the C-phase detection coil 114 generates a voltage pulse when the magnet reference moves from region 2 to region 3. Therefore, the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, can be corrected to the state of each phase detection coil when the magnet reference is positioned in region 3, which is one region jumped in the CW direction from region 1. However, in the second example, the rotation speed is not corrected. In the conversion table of FIG. 8, this correction processing is indicated by "second example".
このように、前回の電圧パルスを発生したときの各相検出コイルの状態、前々回の電圧パルスを発生したときの各相検出コイルの状態、および、今回の電圧パルス(極性および検出コイル)を参照することにより磁石基準の位置の遷移を推定することができる。その結果、不揮発性メモリ127に保持されている各相検出コイルの状態および回転数を補正することが可能となる。
In this way, by referring to the state of each phase detection coil when the previous voltage pulse was generated, the state of each phase detection coil when the last voltage pulse was generated, and the current voltage pulse (polarity and detection coil), the transition of the magnet-based position can be estimated. As a result, it becomes possible to correct the state and rotation speed of each phase detection coil held in the nonvolatile memory 127 .
次に、回転軸115の回転方向が反転した直後のタイミング以外のタイミングで生じるパルス抜けに対する補正処理について、図10を用いて説明する。
Next, correction processing for missing pulses occurring at a timing other than the timing immediately after the rotation direction of the rotating shaft 115 is reversed will be described with reference to FIG.
上述した第1の例および第2の例とは異なり、検出コイルが電圧パルスを発生させた直後に磁石111の回転方向が反転せずに回転し続ける状況、または、磁石111の回転方向が反転した直後にパルス抜けが発生し、その後回転し続ける状況においても、発電部品および検出部品の品質トラブルまたはノイズの影響により、電圧パルスの電圧レベルが低下してパルス抜けが発生する場合が考えられる。この場合においても、電圧パルスの電力を受けて信号処理回路120は動作することができないため、パルス抜けが発生する。その結果、実際の磁石基準の位置と、不揮発性メモリ127に保持されている各相検出コイルの状態から推定される磁石基準の位置とが一致しない現象が発生し得る。
Unlike the first and second examples described above, the magnet 111 may continue to rotate without reversing the direction of rotation immediately after the detection coil generates a voltage pulse, or even in a situation where the missing pulse occurs immediately after the direction of rotation of the magnet 111 is reversed and continues to rotate thereafter, the voltage level of the voltage pulse may drop and the missing pulse may occur due to quality problems or noise in the power generation and detection components. Even in this case, since the signal processing circuit 120 cannot operate by receiving the power of the voltage pulse, a missing pulse occurs. As a result, a phenomenon may occur in which the actual magnet reference position and the magnet reference position estimated from the state of each phase detection coil held in the nonvolatile memory 127 do not match.
ここで、「第3の例」として、図10に示すように、原点位置にB相検出コイル113が配置され、磁石基準が原点位置にある状況から、磁石基準がCW方向に領域6から領域1、領域2、領域3、領域4の順に移動する場合を想定する。図中の実線矢印は実際の磁石111の回転動作を示し、破線矢印は信号処理回路120が認識する磁石111の回転動作を示している。
Here, as a "third example", assume that the B-phase detection coil 113 is arranged at the origin position and the magnet reference is at the origin position as shown in FIG. The solid-line arrows in the drawing indicate the actual rotational movement of the magnet 111 , and the broken-line arrows indicate the rotational movement of the magnet 111 recognized by the signal processing circuit 120 .
まず、磁石基準がCW方向に領域6から領域1へ移動すると、B相検出コイル113から負の電圧パルスが発生する。それに伴い、アダー126は、回転数を+1増加させる。
First, when the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
続いて、磁石基準が領域1から領域2へ移動したときに、A相検出コイル112において、磁界の強度が閾値を超えても、品質トラブルまたはノイズ等に起因して電圧パルスが発生しなかったものとする。
Next, when the magnet reference moves from region 1 to region 2, even if the magnetic field intensity exceeds the threshold in the A-phase detection coil 112, it is assumed that no voltage pulse is generated due to quality problems, noise, or the like.
さらに磁石基準が領域2から領域3へ移動したときに、C相検出コイル114が正の電圧パルスを発生する。
Furthermore, when the magnet reference moves from region 2 to region 3, the C-phase detection coil 114 generates a positive voltage pulse.
この一連の電圧パルスの発生パターンは、上記第1の例における電圧パルスの発生パターンと同じとなる。そのため、アダー126は、第1の例に倣って、回転軸115の回転方向がCCW方向に反転した直後にパルス抜けが生じたものと推定し、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)を、磁石基準が領域5に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)を、磁石基準が領域6に位置するときの各相検出コイルの状態に補正する。さらに、アダー126は、回転数を-1減らす補正をする。ただし、図10から明らかなように、この推定および補正は、実際の磁石111の回転動作とは異なるものである。
This series of voltage pulse generation patterns is the same as the voltage pulse generation pattern in the first example. Therefore, following the first example, the adder 126 presumes that the pulse missing occurred immediately after the rotation direction of the rotating shaft 115 reversed to the CCW direction, corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) held in the nonvolatile memory 127 to the state of each phase detection coil when the magnet reference is positioned in the region 5, and changes the state of each phase detection coil when the last voltage pulse was generated (previous status) to: Correction to the state of each phase detection coil when the magnet reference is positioned in region 6 is performed. Further, the adder 126 makes a correction to reduce the number of revolutions by -1. However, as is clear from FIG. 10 , this estimation and correction are different from the actual rotational motion of the magnet 111 .
続いて、磁石基準がCW方向に領域3から領域4へ移動したときに、B相検出コイル113が正の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準が領域5に位置していた場合には通常発生しないパターンである。また、この発生パターンは、CW方向にてパルス抜けが発生した場合、および、CCW方向への反転直後に生じたパルス抜けの後に、続けてパルス抜けが発生した場合においても、生じ得ないパターンである。
Subsequently, when the magnet reference moves in the CW direction from region 3 to region 4, the B-phase detection coil 113 generates a positive voltage pulse. This pattern of voltage pulse generation is a pattern that would not normally occur if the magnet reference were positioned in region 5 . Also, this generation pattern is a pattern that cannot occur when a missing pulse occurs in the CW direction, or when a missing pulse occurs immediately after the missing pulse occurs immediately after the reversal in the CCW direction.
そこで、アダー126は、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態、前々回の電圧パルスを発生したときの各相検出コイルの状態に加えて、前回および前々回の電圧パルスを発生した検出コイルの情報(検出コイル番号)の履歴を参照する。
Therefore, the adder 126 refers to the history of the state of each phase detection coil when the previous voltage pulse was generated, the state of each phase detection coil when the voltage pulse was generated the time before last, and the information (detection coil number) of the detection coil that generated the voltage pulse last time and the time before last, which are held in the nonvolatile memory 127.
具体的には、前々回の電圧パルスがB相検出コイル113から発生し、かつ、前回の電圧パルスがC相検出コイル114から発生していた場合には、アダー126は、磁石111がCW方向に回転しており、前回の電圧パルスの発生時にパルス抜けが発生したものと推定する。そして、アダー126は、前々回の電圧パルスを発生したときの磁石基準の位置を領域5ではなく、領域3であると推定するとともに、前回の電圧パルスを発生したときの磁石基準の位置を領域4に更新させる。具体的には、アダー126は、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)について、磁石基準が領域4に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)について、磁石基準が領域3に位置するときの各相検出コイルの状態に補正する。さらに、アダー126は、回転数を+1増加させる補正を行い、不揮発性メモリ127に格納する。図9の変換テーブルでは、この補正処理が「第3の例」で示されている。
Specifically, when the last voltage pulse was generated from the B-phase detection coil 113 and the previous voltage pulse was generated from the C-phase detection coil 114, the adder 126 presumes that the magnet 111 is rotating in the CW direction and that a missing pulse occurred when the previous voltage pulse was generated. Then, the adder 126 estimates that the position of the magnet reference when the last voltage pulse was generated is not region 5 but region 3, and updates the position of the magnet reference when the previous voltage pulse is generated to region 4. Specifically, the adder 126 corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, to the state of each phase detection coil when the magnet reference is located in region 4, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated before the last time to the state of each phase detection coil when the magnet reference is located in region 3. Further, the adder 126 performs a correction to increase the rotational speed by +1, and stores the result in the nonvolatile memory 127 . In the conversion table of FIG. 9, this correction processing is indicated by "third example".
なお、上記パターンにおいて、前々回の電圧パルスがB相検出コイル113以外から発生していた場合には、推定される動きではないことが分かるため、アダー126は補正を行わず、エラーを出力する。
It should be noted that, in the above pattern, if the voltage pulse of the time before last was generated from other than the B-phase detection coil 113, it is known that the movement is not estimated, so the adder 126 does not perform correction and outputs an error.
次に、「第4の例」として、磁石111の回転方向が反転した直後にパルス抜けが発生し、これに連続してパルス抜けが発生した場合を想定する。例えば、原点位置にB相検出コイル113が配置され、磁石基準が原点位置にある状況から、磁石基準がCW方向に領域6から領域1に移動し、その後、回転方向の反転により、磁石基準がCCW方向に領域6、領域5、領域4の順に移動する場合を想定する。
Next, as a "fourth example", it is assumed that a missing pulse occurs immediately after the direction of rotation of the magnet 111 is reversed, followed by another missing pulse. For example, assume that the B-phase detection coil 113 is placed at the origin position and the magnet reference is at the origin position, the magnet reference moves in the CW direction from area 6 to area 1, and then, due to the reversal of the rotation direction, the magnet reference moves in the CCW direction in the order of area 6, area 5, and area 4.
まず、磁石基準がCW方向に領域6から領域1へ移動すると、B相検出コイル113から負の電圧パルスが発生する。それに伴い、アダー126は、回転数を+1増加させる。
First, when the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
続いて、磁石111の回転方向が反転し、磁石基準がCCW方向に領域1から領域6へ戻るときに、B相検出コイル113においてパルス抜けが発生した場合には、不揮発性メモリ127は、磁石基準が領域1に位置するときの各相検出コイルの状態を保持する。
Subsequently, when the rotation direction of the magnet 111 is reversed and the magnet reference returns from area 1 to area 6 in the CCW direction, and a pulse missing occurs in the B-phase detection coil 113, the nonvolatile memory 127 holds the state of each phase detection coil when the magnet reference is positioned in area 1.
続いて、磁石基準がCCW方向に領域6から領域5へ移動したときに、C相検出コイル114において、磁界の強度が閾値を超えても、品質トラブルまたはノイズ等に起因して電圧パルスが発生しなかったものとする。
Next, when the magnet reference moves from area 6 to area 5 in the CCW direction, even if the magnetic field intensity exceeds the threshold value in the C-phase detection coil 114, it is assumed that no voltage pulse is generated due to quality problems, noise, or the like.
さらに磁石基準がCCW方向に領域5から領域4へ移動したときに、A相検出コイル112が負の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準がCW方向に領域1から領域2へ移動したときと同じ発生パターンとなる。そのため、アダー126は、磁石基準が領域2に位置するものと推定し、不揮発性メモリ127に、現在のステータスとして、磁石基準が領域2に位置するときの各相検出コイルの状態を保持する。
Furthermore, when the magnet reference moves from area 5 to area 4 in the CCW direction, phase A detection coil 112 generates a negative voltage pulse. The voltage pulse generation pattern is the same as when the magnet reference moves from region 1 to region 2 in the CW direction. Therefore, adder 126 presumes that the magnet reference is located in region 2, and holds the state of each phase detection coil when the magnet reference is located in region 2 as the current status in non-volatile memory 127 .
さらに続けて、磁石基準がCCW方向に領域4から領域3へ移動したときに、B相検出コイル113が負の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準が領域2に位置していた場合には通常生じないパターンである。そこで、アダー126は、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態、および、前々回の電圧パルスを発生したときの各相検出コイルの状態に加えて、前回および前々回の電圧パルスを発生した検出コイル(検出コイル番号)の履歴を参照する。
Furthermore, when the magnet reference moves from area 4 to area 3 in the CCW direction, the B-phase detection coil 113 generates a negative voltage pulse. This voltage pulse generation pattern is a pattern that would not normally occur if the magnet reference were located in region 2 . Therefore, the adder 126 refers to the state of each phase detection coil when the previous voltage pulse was generated and the state of each phase detection coil when the last voltage pulse was generated, which are held in the nonvolatile memory 127, as well as the history of the detection coils (detection coil numbers) that generated the previous and two previous voltage pulses.
具体的には、前々回の電圧パルスがB相検出コイル113から発生していた場合には、アダー126は、磁石111が実際にはCCW方向に回転しており、前回の電圧パルスの発生時にパルス抜けが発生したものと推定する。この場合、アダー126は、前々回の電圧パルスが発生したときの磁石基準の位置を領域2ではなく、領域4であると推定するとともに、前回の電圧パルスを発生したときの磁石基準の位置を領域3に更新させる。具体的には、アダー126は、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)を、磁石基準が領域3に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)を、磁石基準が領域4に位置するときの各相検出コイルの状態に補正する。さらに、アダー126は、回転数を-1減少させる補正を行い、不揮発性メモリ127に格納する。図8の変換テーブルでは、この補正処理が「第4の例」で示されている。
Specifically, when the voltage pulse the last time was generated from the B-phase detection coil 113, the adder 126 presumes that the magnet 111 is actually rotating in the CCW direction, and that the missing pulse occurred when the previous voltage pulse was generated. In this case, the adder 126 estimates that the magnet reference position when the last voltage pulse was generated is not region 2 but region 4, and updates the magnet reference position when the previous voltage pulse was generated to region 3. Specifically, the adder 126 corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127, to the state of each phase detection coil when the magnet reference is located in region 3, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated the last time before to the state of each phase detection coil when the magnet reference is located in region 4. Further, the adder 126 performs a correction to decrease the number of revolutions by -1, and stores the result in the nonvolatile memory 127 . In the conversion table of FIG. 8, this correction processing is indicated by "fourth example".
なお、前回の電圧パルスを発生した検出コイル(検出コイル番号)と同じ検出コイルから電圧パルスが発生し、かつ、両者の電圧パルスの極性も同じである場合には、更新後の磁石基準が位置する領域と、更新前の磁石基準が位置する領域とが同じとなる。この場合、コントローラ125は、電圧パルスを発生した検出コイルの情報(検出コイル番号)の履歴を更新し、それ以外の情報は不揮発性メモリ127から読み出した情報をそのまま不揮発性メモリ127に書き込むこととする。これは、検出コイルの情報(検出コイル番号)の履歴を更新すると、補正時に参照される、前々回の電圧パルスを検出した検出コイルの情報が更新されるため、補正が可能なパターンであっても、変換テーブル(図8および図9参照)に示される変換パターンに合致しなくなり、エラーが出力されることになるためである。
When a voltage pulse is generated from the same detection coil (detection coil number) as the detection coil (detection coil number) that generated the previous voltage pulse, and the polarities of both voltage pulses are also the same, the area where the magnet reference after updating is located and the area where the magnet reference before updating is located are the same. In this case, the controller 125 updates the history of the information (detection coil number) of the detection coil that generated the voltage pulse, and writes the other information read from the nonvolatile memory 127 to the nonvolatile memory 127 as it is. This is because when the history of the detection coil information (detection coil number) is updated, the information of the detection coil that detected the voltage pulse of the time before last, which is referred to during correction, is updated. Therefore, even if the pattern is correctable, it will no longer match the conversion pattern shown in the conversion table (see FIGS. 8 and 9), and an error will be output.
また、パルス抜けが発生した直後から実際に補正が実行されるまでの期間は、磁石基準が実際に位置する領域と、不揮発性メモリ127に保持されている、現在のステータスにおける磁石基準が位置する領域とが異なることとなる。そのため、当該期間中に回転数の読み出し動作が行われると、読み出された回転数が実際の回転数に一致していない場合が起こり得る。
Also, during the period from immediately after the occurrence of the missing pulse until the correction is actually performed, the area where the magnet reference is actually located differs from the area where the magnet reference in the current status held in the nonvolatile memory 127 is located. Therefore, if the number of revolutions is read out during this period, the read number of revolutions may not match the actual number of revolutions.
ただし、外部電源から電力が供給されている状態で回転数が読み出されることから、外部電源を用いた別の手段(例えば、光学式、機械式または磁気式のエンコーダなど)によって磁石基準の位置を正確に確認することができる。これによると、磁石基準が位置する領域と、不揮発性メモリ127に記憶されている磁石基準が位置する領域とを比較し、不一致の場合にはエラーを出力する構成とすることにより、補正前の回転数が読み出されることを防ぐことができる。なお、不一致を判断するときには、回転方向の反転によるパルス抜けが発生した場合も考慮し、現在の磁石基準が位置する領域だけでなく、前回の磁石基準が位置する領域も一致するか否かを判断することが望ましい。さらに、検出コイルのヒステリシス特性(図3参照)を考慮し、電圧パルスが発生するときの位相が一致するか否かを判断することが望ましい。
However, since the number of rotations is read while power is being supplied from an external power supply, another means using an external power supply (for example, an optical, mechanical, or magnetic encoder) can be used to accurately confirm the position of the magnet reference. According to this, the area where the magnet reference is located is compared with the area where the magnet reference stored in the nonvolatile memory 127 is located, and if they do not match, an error is output, thereby preventing the number of revolutions before correction from being read out. When judging mismatch, it is preferable to judge whether or not not only the area where the current magnet reference is located but also the area where the previous magnet reference is located match, considering the case where the pulse missing due to the reversal of the rotation direction occurs. In addition, it is desirable to consider the hysteresis characteristics of the detection coil (see FIG. 3) to determine whether the phases of the voltage pulses match.
なお、磁石111の回転方向が反転せずにパルス抜けが2回連続して発生する状況、および、磁石111の回転方向が反転した後にパルス抜けが3回連続して発生する状況は非常に限定的ではあるが、仮にこれらの状況が発生した場合には、前回の電圧パルスを発生した検出コイルと、今回の電圧パルスを発生した検出コイルとが同じであると見なされる。一方、実際に磁石基準が位置する領域は、電圧パルスを発生したときの各相検出コイルの状態から推定される磁石基準が位置する領域とは対称となる領域に移動している。そのため、これ以降の磁石基準の移動によって生じる電圧パルスは、推定される磁石基準の移動によって生じる電圧パルスとは反対の極性となる。この場合、前々回の電圧パルスを発生した検出コイルの情報(検出コイル番号)を参照することにより、図8および図9の変換テーブルに記載される何れの変換パターンにも該当しないため、エラーが出力されることとなる。したがって、磁石基準が位置する領域が実際に磁石基準が位置する領域とは異なる領域に補正されることがない。その結果、誤った補正に起因する回転数の誤検出を回避することができるため、回転軸115が停止位置を行き過ぎてしまう過走、および回転軸115の位置ずれ等の重大な事故を未然に防ぐことが可能となる。
It should be noted that the situation in which two consecutive missing pulses occur without reversing the direction of rotation of the magnet 111, and the situation in which three consecutive missing pulses occur after the direction of rotation of the magnet 111 is reversed are very limited. On the other hand, the region where the magnet reference is actually located moves to a region symmetrical to the region where the magnet reference is estimated from the state of each phase detection coil when the voltage pulse is generated. As such, voltage pulses resulting from subsequent movements of the magnet reference will be of opposite polarity to voltage pulses resulting from presumed movements of the magnet reference. In this case, by referring to the information (detection coil number) of the detection coil that generated the voltage pulse before the last time, it does not correspond to any of the conversion patterns described in the conversion tables of FIGS. 8 and 9, so an error is output. Therefore, the area where the magnet reference is positioned is not corrected to be different from the area where the magnet reference is actually positioned. As a result, erroneous detection of the number of revolutions due to erroneous correction can be avoided, and serious accidents such as overrunning in which the rotating shaft 115 overshoots the stop position and displacement of the rotating shaft 115 can be prevented.
なお、前回の電圧パルスを発生したときに磁石基準が位置する領域は、磁石基準がCW/CCWの何れの方向で現在の位置に移動したかの情報を有することによって、一意に決定することができる。そのため、磁石基準の移動方向を示す情報を用いることにより、不揮発性メモリ127に記憶される情報量を削減することが可能となる。
It should be noted that the area where the magnet reference is located when the previous voltage pulse was generated can be uniquely determined by having information on which direction, CW/CCW, the magnet reference has moved to the current position. Therefore, the amount of information stored in the nonvolatile memory 127 can be reduced by using the information indicating the magnet-based moving direction.
さらに、前々回の電圧パルスを発生した検出コイルの情報は、前回の磁石基準が位置する領域と前々回の磁石基準が位置する領域との差から求めることができるため、当該差の情報を用いてもよい。
Furthermore, information on the detection coil that generated the voltage pulse before the last can be obtained from the difference between the area where the previous magnet reference is located and the area where the magnet reference before the previous is located, so the information on the difference may be used.
なお、反転パルスが検知された場合でも、コントローラ125は、不揮発性メモリ127の情報を更新せず、次に発生する電圧パルスの処理において、反転パルス抜けが発生した場合と同じように扱うことも可能である。
It should be noted that even if an inversion pulse is detected, the controller 125 does not update the information in the nonvolatile memory 127, and in processing the next generated voltage pulse, it is possible to handle it in the same way as if the inversion pulse was missing.
以上説明したように、実施の形態1に従う回転検出器によれば、今回の電圧パルス(極性および検出コイル)、並びに、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態、前々回の電圧パルスを発生したときの各相検出コイルの状態、および、前回および前々回の電圧パルスを発生した検出コイルの情報(検出コイル番号)の履歴を参照することにより、磁石111の回転方向が反転した直後のタイミングで生じるパルス抜けだけでなく、上記タイミング以外のタイミングで生じるパルス抜けを検知することができる。そして、何れのパルス抜けに対しても、上記の情報を用いて、不揮発性メモリ127に保持される各相検出コイルの状態(磁石基準の位置)および回転軸115の回転数を補正することができる。その結果、パルス抜けに対する回転数の補正精度を高めることが可能となる。
As described above, according to the rotation detector according to the first embodiment, by referring to the history of the current voltage pulse (polarity and detection coil), the state of each phase detection coil when the previous voltage pulse was generated, the state of each phase detection coil when the voltage pulse was generated before the previous time, and the information (detection coil number) of the detection coil that generated the voltage pulse the last time and the time before the time before, which are held in the nonvolatile memory 127, is generated at the timing immediately after the rotation direction of the magnet 111 is reversed. It is possible to detect not only missing pulses but also missing pulses that occur at timings other than the above timings. Then, for any missing pulse, the state of each phase detection coil (position based on the magnet) and the rotation speed of the rotating shaft 115 held in the nonvolatile memory 127 can be corrected using the above information. As a result, it is possible to improve the accuracy of correcting the number of revolutions for missing pulses.
実施の形態2.
図11は、実施の形態2に従う回転検出器の全体構成を示す図である。図11に示すように、実施の形態2に従う回転検出器101Aは、信号処理回路120に代えて信号処理回路120Aを備える点が図1に示した回転検出器101とは異なる。Embodiment 2.
FIG. 11 is a diagram showing the overall configuration of the rotation detector according to the second embodiment. As shown in FIG. 11,rotation detector 101A according to the second embodiment differs from rotation detector 101 shown in FIG.
図11は、実施の形態2に従う回転検出器の全体構成を示す図である。図11に示すように、実施の形態2に従う回転検出器101Aは、信号処理回路120に代えて信号処理回路120Aを備える点が図1に示した回転検出器101とは異なる。
FIG. 11 is a diagram showing the overall configuration of the rotation detector according to the second embodiment. As shown in FIG. 11,
信号処理回路120Aは、図1に示した信号処理回路120におけるコントローラ125、アダー126および不揮発性メモリ127を、コントローラ125A、アダー126Aおよび不揮発性メモリ127Aにそれぞれ置き換えたものである。
The signal processing circuit 120A replaces the controller 125, adder 126 and nonvolatile memory 127 in the signal processing circuit 120 shown in FIG.
不揮発性メモリ127Aは、回転軸115の回転数、電圧パルスが生じたときの各相検出コイルの状態、および電圧パルスを発生した検出コイルの情報(検出コイル番号)の履歴に加えて、前回の更新処理で補正が実施されたことを示す「補正実施フラグ」を記憶するように構成される。不揮発性メモリ127Aは、さらに、図12および図13に示す変換テーブルを記憶する。
The non-volatile memory 127A is configured to store a "correction execution flag" indicating that correction has been performed in the previous update process, in addition to a history of the number of rotations of the rotary shaft 115, the state of each phase detection coil when a voltage pulse is generated, and information (detection coil number) of the detection coil that generated the voltage pulse. Nonvolatile memory 127A further stores conversion tables shown in FIGS.
補正実施フラグは、図12および図13に示す変換テーブルにおいて、更新後の情報に追加されている。補正実施フラグは、前回の更新処理において補正が実施された場合に「1」に設定され、補正が実施されなかった場合に「0」に設定される。
The correction implementation flag is added to the updated information in the conversion tables shown in FIGS. The correction execution flag is set to "1" when correction is executed in the previous update process, and is set to "0" when correction is not executed.
コントローラ125Aは、不揮発性メモリ127Aにアクセスし、前回の電圧パルスが生じたときの回転軸115の回転数と、前回の電圧パルスを発生したときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報と、前々回の電圧パルスを発生したときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報と、補正実施フラグとを不揮発性メモリ127Aから読み出す。コントローラ125は、読み出したこれらの情報をアダー126へ送信する。
The controller 125A accesses the non-volatile memory 127A and reads from the non-volatile memory 127A the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information about the detection coil that output the voltage pulse, the state of each phase detection coil when the voltage pulse was generated the last time before, the information about the detection coil that output the voltage pulse, and the correction execution flag. The controller 125 transmits the read information to the adder 126 .
アダー126Aは、コントローラ125Aから受信した情報(今回の電圧パルスの情報および不揮発性メモリ127Aから読み出した情報)に基づいて、変換テーブル(図12および図13参照)を用いて、更新処理を実行する。この更新処理において、アダー126Aは、不揮発性メモリ127Aに保持されている各相検出コイルの状態(磁石基準の位置)を補正する処理を行った場合には、補正実施フラグを1に設定する。また、アダー126Aは、更新処理において、不揮発性メモリ127Aから読み出した補正実施フラグが1であり、かつ、磁石基準の位置を補正するような更新処理が行われた場合には、エラーを出力する。
The adder 126A executes update processing using the conversion table (see FIGS. 12 and 13) based on the information received from the controller 125A (the current voltage pulse information and the information read from the nonvolatile memory 127A). In this update process, the adder 126A sets the correction execution flag to 1 when the process of correcting the state of each phase detection coil (the magnet reference position) held in the nonvolatile memory 127A is performed. Further, the adder 126A outputs an error when the correction execution flag read from the nonvolatile memory 127A is 1 and the update process for correcting the magnet-based position is performed in the update process.
コントローラ125Aは、再度不揮発性メモリ127Aにアクセスし、アダー126Aから受信した情報および更新後の検出コイルの情報の履歴を不揮発性メモリ127Aに書き込む。
The controller 125A accesses the non-volatile memory 127A again and writes the history of the information received from the adder 126A and the updated information of the detection coil into the non-volatile memory 127A.
実施の形態2では、補正実施フラグが1の状態で、次の更新処理でも補正を実施するようなパターンが発生した場合にはエラーを出力するように構成される。これによると、装置の稼働を継続できなくなるが、誤った回転数の読み出しを回避することができる。以下、実施の形態2に従う更新処理について説明する。
In the second embodiment, when the correction execution flag is set to 1, an error is output when a pattern occurs in which correction is to be executed even in the next update process. Although this makes it impossible to continue the operation of the apparatus, it is possible to avoid reading an erroneous number of revolutions. Update processing according to the second embodiment will be described below.
ここで、「第5の例」として、原点位置にB相検出コイル113が配置され、磁石基準が領域5にある状況から、磁石基準がCW方向に領域5から領域6、領域1、領域2へ順に移動し、その後、磁石111の回転方向が反転して磁石基準がCCW方向に領域2から領域1へ移動した場合を想定する。
Here, as a "fifth example", assume that the B-phase detection coil 113 is placed at the origin position and the magnet reference is in region 5, and the magnet reference moves in the CW direction from region 5 to region 6, then to region 1 and then to region 2, and then the rotation direction of the magnet 111 is reversed and the magnet reference moves in the CCW direction from region 2 to region 1.
最初に、磁石基準がCW方向に領域5から領域6へ移動したときに、C相検出コイル114が負の電圧パルスを発生する。さらに、磁石基準がCW方向に領域6から領域1に移動したときに、B相検出コイル113が負の電圧パルスを発生する。これに伴い、アダー126Aは、回転数を+1増加させる。
First, when the magnet reference moves in the CW direction from region 5 to region 6, phase C detection coil 114 generates a negative voltage pulse. Additionally, when the magnet reference moves CW from region 6 to region 1, phase B detection coil 113 generates a negative voltage pulse. Along with this, the adder 126A increases the rotational speed by +1.
その後、磁石基準がCW方向に領域1から領域2に移動するが、品質トラブルまたはノイズ等に起因してA相検出コイル112の電圧パルスが発生しないパルス抜けが生じたものとする。このパルス抜けによって、不揮発性メモリ127Aは、磁石基準の位置が領域1であるときの各相検出コイルの状態を保持する。
After that, the magnet reference moves from area 1 to area 2 in the CW direction, but due to quality problems or noise, the A-phase detection coil 112 does not generate a voltage pulse, which is a missing pulse. Due to this missing pulse, the nonvolatile memory 127A retains the state of each phase detection coil when the magnet reference position is region 1 .
その後、磁石111の回転方向がCCW方向に反転し、磁石基準が領域2から領域1へ戻ったときに、A相検出コイル112は正の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準が領域1に位置する場合には、通常起こり得ないパターンである。そこで、アダー126Aは、図12および図13の変換テーブルに従って、前々回の電圧パルスをC相検出コイル114が発生したという情報を用いて補正を行う。このとき、アダー126Aは、補正実施フラグを1に設定する。
After that, when the rotation direction of the magnet 111 reverses to the CCW direction and the magnet reference returns from region 2 to region 1, the A-phase detection coil 112 generates a positive voltage pulse. This voltage pulse generation pattern is a pattern that normally cannot occur when the magnet reference is located in region 1. FIG. Therefore, the adder 126A performs correction using the information that the C-phase detection coil 114 generated the voltage pulse of the time before last according to the conversion tables of FIGS. At this time, the adder 126A sets the correction execution flag to 1.
この場合、アダー126Aは、前々回の電圧パルスが発生したときの磁石基準の位置を領域1ではなく、領域4であると推定するとともに、前回の電圧パルスを発生したときの磁石基準の位置を領域5に更新させる。具体的には、アダー126Aは、不揮発性メモリ127Aに保持されている、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)を、磁石基準が領域5に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)を、磁石基準が領域4に位置するときの各相検出コイルの状態に補正する。さらに、アダー126Aは、回転数を-1減少させる補正を行い、補正実施フラグ(=1)とともに不揮発性メモリ127Aに格納する。ただし、この処理は、実際の磁石基準の位置に補正する処理ではなく、誤った補正となる。
In this case, the adder 126A estimates that the magnet reference position when the last voltage pulse was generated is not area 1 but area 4, and updates the magnet reference position when the previous voltage pulse was generated to area 5. Specifically, the adder 126A corrects the state (current status) of each phase detection coil when the previous voltage pulse was generated, which is held in the nonvolatile memory 127A, to the state of each phase detection coil when the magnet reference is located in region 5, and corrects the state of each phase detection coil (previous status) when the voltage pulse was generated before the previous time to the state of each phase detection coil when the magnet reference is located in region 4. Further, the adder 126A performs a correction to decrease the number of revolutions by -1, and stores the result together with a correction execution flag (=1) in the non-volatile memory 127A. However, this process is not a process of correcting to the actual magnet reference position, but an erroneous correction.
この後、磁石基準がCCW方向にさらに移動し、磁石基準が領域1から領域6に移動したときに、B相検出コイル113が正の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準が領域5に位置する場合には、通常起こり得ないパターンである。図12および図13の変換テーブルに従った場合、磁石基準が領域5ではなく領域1に位置したものと推定し、更新後の領域を領域6に移動させるとともに、回転数を-1減少させる。しかしながら、上記2つの補正処理によって磁石基準の位置は最終的に実際の位置に戻ることとなるが、回転数が実際の回転数に対して1足りない状態となってしまう。
After that, when the magnet reference moves further in the CCW direction and moves from region 1 to region 6, the B-phase detection coil 113 generates a positive voltage pulse. This voltage pulse generation pattern is a pattern that normally cannot occur when the magnet reference is located in region 5 . 12 and 13, it is assumed that the magnet reference is located in region 1 instead of region 5, the updated region is moved to region 6, and the number of revolutions is decreased by -1. However, although the position of the magnet reference is finally returned to the actual position by the two correction processes described above, the number of revolutions becomes one less than the actual number of revolutions.
そこで、実施の形態2では、補正実施フラグが1である状態で更新処理を行うときに、さらに続けて補正を行う処理となる場合には、エラーを出力することとする。これにより、装置の稼働を継続できなくなるが、誤った回転数の読み出しを回避することができる。
Therefore, in the second embodiment, when the update process is performed with the correction execution flag set to 1, an error is output if the correction process continues. This makes it impossible to continue the operation of the device, but it is possible to avoid reading an erroneous number of revolutions.
以上説明したように、実施の形態2に従う回転検出器によれば、検出コイルのパルス抜けと複数回の回転方向の反転動作とが組み合わさった場合に生じる回転数の誤検出を、補正実施フラグを参照することによって回避することができる。その結果、回転軸115の回転方向に対する制約をなくすことが可能となる。
As described above, according to the rotation detector according to the second embodiment, it is possible to avoid erroneous detection of the number of rotations caused by a combination of missing pulses in the detection coil and reversing the rotation direction a plurality of times by referring to the correction execution flag. As a result, it is possible to eliminate restrictions on the rotation direction of the rotating shaft 115 .
実施の形態3.
図14は、実施の形態3に従う回転検出器の全体構成を示す図である。図14に示すように、実施の形態3に従う回転検出器101Bは、信号処理回路120に代えて信号処理回路120Bを備える点が図1に示した回転検出器101とは異なる。Embodiment 3.
FIG. 14 is a diagram showing the overall configuration of a rotation detector according toEmbodiment 3. FIG. As shown in FIG. 14, rotation detector 101B according to the third embodiment differs from rotation detector 101 shown in FIG.
図14は、実施の形態3に従う回転検出器の全体構成を示す図である。図14に示すように、実施の形態3に従う回転検出器101Bは、信号処理回路120に代えて信号処理回路120Bを備える点が図1に示した回転検出器101とは異なる。
FIG. 14 is a diagram showing the overall configuration of a rotation detector according to
信号処理回路120Bは、図1に示した信号処理回路120におけるコントローラ125を、コントローラ125Bに置き換えたものである。
The signal processing circuit 120B is obtained by replacing the controller 125 in the signal processing circuit 120 shown in FIG. 1 with a controller 125B.
コントローラ125Bは、不揮発性メモリ127にアクセスし、前回の電圧パルスが生じたときの回転軸115の回転数と、前回の電圧パルスが生じたときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報(検出コイル番号)と、前々回の電圧パルスが生じたときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報(検出コイル番号)とを不揮発性メモリ127から読み出す。コントローラ125Bは、読み出したこれらの情報をアダー126へ送信する。
The controller 125B accesses the non-volatile memory 127 and reads from the non-volatile memory 127 the number of rotations of the rotating shaft 115 when the previous voltage pulse was generated, the state of each phase detection coil when the previous voltage pulse was generated, the information of the detection coil that output the voltage pulse (detection coil number), and the state of each phase detection coil when the voltage pulse was generated two before before and the information of the detection coil that output the voltage pulse (detection coil number). The controller 125B transmits the read information to the adder 126. FIG.
アダー126により更新処理が実行された後、コントローラ125Bは、不揮発性メモリ127に再びアクセスし、アダー126からの情報および更新後の検出コイルの情報を不揮発性メモリ127に書き込む。
After the update process is executed by the adder 126, the controller 125B accesses the non-volatile memory 127 again and writes the information from the adder 126 and the updated detection coil information into the non-volatile memory 127.
このとき、コントローラ125Bは、前回の電圧パルスを発生した検出コイルの情報と、今回の電圧パルスを発生した検出コイルの情報とが同じであるか否かを判定する。これら2つの情報が同じである場合には、コントローラ125Bは、不揮発性メモリ127に保持される情報を更新することなく、不揮発性メモリ127から読み出した情報をそのまま書き込む。あるいは、不揮発性メモリ127が非破壊読み出しメモリである場合には、コントローラ125Bは、書き込みをせずに前回値を保持する。一方、上記2つの情報が異なる場合には、コントローラ125Bは、通常の更新処理を行い、各相検出コイルの状態、回転数、および検出コイルの情報を不揮発性メモリ127に書き込む。
At this time, the controller 125B determines whether or not the information about the detection coil that generated the previous voltage pulse is the same as the information about the detection coil that generated the current voltage pulse. If these two pieces of information are the same, the controller 125B writes the information read from the nonvolatile memory 127 without updating the information held in the nonvolatile memory 127 . Alternatively, if the non-volatile memory 127 is a non-destructive read-out memory, the controller 125B holds the previous value without writing. On the other hand, if the above two pieces of information are different, the controller 125B performs normal update processing, and writes the state of each phase detection coil, the number of revolutions, and the detection coil information to the nonvolatile memory 127 .
実施の形態3では、上述した実施の形態1および2では補正することができなかったパターンでも補正を行い、回転検出器101Bの動作を継続させることが可能となる。以下、実施の形態3に従う更新処理について説明する。
In Embodiment 3, even patterns that could not be corrected in Embodiments 1 and 2 described above are corrected, and the operation of the rotation detector 101B can be continued. Update processing according to the third embodiment will be described below.
ここで、「第6の例」として、原点位置にB相検出コイル113が配置され、磁石基準が原点位置にある状況から、磁石基準がCW方向に領域6から領域1、領域2、領域3へ順に移動し、その後、磁石111の回転方向が反転して磁石基準がCCW方向に領域3から領域2、領域1へ順に移動した場合を想定する。
Here, as a "sixth example", it is assumed that the B-phase detection coil 113 is arranged at the origin position and the magnet reference is at the origin position, and the magnet reference moves in the CW direction from area 6 to area 1, area 2, and area 3 in order, and then the rotation direction of the magnet 111 is reversed, and the magnet reference moves in the CCW direction from area 3 to area 2 and then to area 1 in order.
最初に、磁石基準がCW方向に領域6から領域1へ移動したときに、B相検出コイル113が負の電圧パルスを発生する。これに伴い、アダー126は、回転数を+1増加させる。
First, when the magnet reference moves in the CW direction from region 6 to region 1, the B-phase detection coil 113 generates a negative voltage pulse. Along with this, the adder 126 increases the rotational speed by +1.
続いて、磁石基準がCW方向に領域1から領域2に移動するが、品質またはノイズ等に起因してA相検出コイル112の電圧パルスが発生しないパルス抜けが生じたものとする。このパルス抜けによって、不揮発性メモリ127は、磁石基準の位置が領域1であるときの各相検出コイルの状態を保持する。
Next, it is assumed that the magnet reference moves in the CW direction from area 1 to area 2, but due to quality, noise, or the like, no voltage pulse is generated in the A-phase detection coil 112, causing a missing pulse. Due to this missing pulse, the nonvolatile memory 127 retains the state of each phase detection coil when the magnet reference position is region 1 .
その後、磁石基準がCW方向に領域2から領域3へ移動したときに、C相検出コイル114が正の電圧パルスを発生する。この電圧パルスの発生パターンは、実施の形態1で説明した「第1の例」と同じ発生パターンとなる。このため、アダー126は、回転方向が反転した直後にパルス抜けが発生したものと推定し、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)を、磁石基準が領域5に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)を、磁石基準が領域6に位置するときの各相検出コイルの状態に補正する。さらに、アダー126は、回転数を-1減少させる。
After that, when the magnet reference moves in the CW direction from region 2 to region 3, the C-phase detection coil 114 generates a positive voltage pulse. The voltage pulse generation pattern is the same as the "first example" described in the first embodiment. Therefore, the adder 126 presumes that the missing pulse has occurred immediately after the rotation direction is reversed, corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) to the state of each phase detection coil when the magnet reference is located in region 5, and corrects the state of each phase detection coil when the voltage pulse was generated the last time (previous status) to the state of each phase detection coil when the magnet reference is located in region 6. Further, the adder 126 reduces the number of revolutions by -1.
その後、磁石111の回転方向がCCW方向に反転し、磁石基準が領域3から領域2へ戻ったときに、C相検出コイル114が負の電圧パルスを発生する。このとき、前回の電圧パルスを発生した検出コイルと今回の電圧パルスを発生した検出コイルが同じC相検出コイル114であるため、アダー126は、磁石基準の領域および検出コイルの情報を更新しない。
After that, when the rotation direction of the magnet 111 reverses to the CCW direction and the magnet reference returns from region 3 to region 2, the C-phase detection coil 114 generates a negative voltage pulse. At this time, since the detection coil that generated the previous voltage pulse and the detection coil that generated the current voltage pulse are the same C-phase detection coil 114, the adder 126 does not update the magnet reference area and detection coil information.
その後、磁石111がCCW方向に回転し、磁石基準が領域2から領域1に移動したときに、A相検出コイル112が正の電圧パルスを発生する。この電圧パルスの発生パターンは、磁石基準が領域5に位置する場合には、通常起こり得ないパターンである。そこで、アダー126は、電圧パルスを発生した検出コイルの情報の履歴を参照する。前々回の電圧パルスをA相検出コイル112が発生していた場合には、アダー126は、実際の前回の電圧パルスの発生時ではなく、不揮発性メモリ127に保持されている前回の電圧パルスの発生時において、反転抜けとは異なるパルス抜けが発生しており、実際には磁石基準がCW方向に移動していたものと推定する。
After that, when the magnet 111 rotates in the CCW direction and the magnet reference moves from region 2 to region 1, the A-phase detection coil 112 generates a positive voltage pulse. This voltage pulse generation pattern is a pattern that normally cannot occur when the magnet reference is located in region 5 . Therefore, the adder 126 refers to the information history of the detection coil that generated the voltage pulse. When the A-phase detection coil 112 has generated the voltage pulse before the previous one, the adder 126 presumes that a missing pulse different from a missing reversal occurred when the previous voltage pulse held in the non-volatile memory 127 was generated, not when the previous voltage pulse was actually generated, and that the magnet reference actually moved in the CW direction.
この場合、アダー126は、前々回の電圧パルスを発生したときの磁石基準の位置が領域5ではなく領域3であり、そこから回転方向が反転した直後にパルス抜けが発生し、そのまま磁石基準がCCW方向へ移動したものと推定する。そこで、アダー126は、不揮発性メモリ127に保持されている、前回の電圧パルスを発生したときの磁石基準の位置を領域1に移動させるとともに、回転数を+1増加させる補正を行う。具体的には、アダー126は、前回の電圧パルスを発生したときの各相検出コイルの状態(現在のステータス)を、磁石基準が領域1に位置するときの各相検出コイルの状態に補正するとともに、前々回の電圧パルスを発生したときの各相検出コイルの状態(前回のステータス)を、磁石基準が領域2に位置するときの各相検出コイルの状態に補正して、不揮発性メモリ127に格納する。さらに、アダー126は、回転数を+1増加させる補正を行い、不揮発性メモリ127に格納する。
In this case, the adder 126 presumes that the position of the magnet reference when the last voltage pulse was generated was not the region 5 but the region 3, and the missing pulse occurred immediately after the rotation direction was reversed from there, and the magnet reference moved in the CCW direction as it was. Therefore, the adder 126 moves the position of the magnet reference when the previous voltage pulse was generated, which is stored in the nonvolatile memory 127, to region 1, and corrects the rotational speed by +1. Specifically, the adder 126 corrects the state of each phase detection coil when the previous voltage pulse was generated (current status) to the state of each phase detection coil when the magnet reference is located in region 1, and also corrects the state of each phase detection coil when the last voltage pulse was generated (previous status) to the state of each phase detection coil when the magnet reference is located in region 2, and stores them in the nonvolatile memory 127. Further, the adder 126 performs a correction to increase the rotational speed by +1, and stores the result in the nonvolatile memory 127 .
ここで、上記の第6の例において、実施の形態1に従う更新処理を実行する場合を考える。磁石基準がCCW方向に領域3から領域2に移動したときに、不揮発性メモリ127に保持される、回転軸115の回転数、前回および前々回の電圧パルスを生じたときの各相検出コイルの状態、および電圧パルスを出力した検出コイルの情報(検出コイル番号)が更新される。このとき、前回の電圧パルスが生じたときの磁石基準の位置が領域6とされ、前々回の電圧パルスが生じたときの磁石基準の位置が領域5とされる。また、前回の電圧パルスをC相検出コイル114が発生し、前々回の電圧パルスをC相検出コイル114が発生したとされる。その後、磁石基準がCCW方向に領域2から領域1へ移動したときに発生する電圧パルスは、磁石基準が領域6に位置するときには通常発生しないパターンとなる。前々回の電圧パルスを発生した検出コイルが一致しないため、何れの補正パターンにも該当せず、結果的にエラーが出力されることとなる。
Here, consider the case of executing the update process according to the first embodiment in the above sixth example. When the magnet reference moves from area 3 to area 2 in the CCW direction, the rotation speed of rotating shaft 115, the state of each phase detection coil when the voltage pulse was generated last time and the time before last, and the information (detection coil number) of the detection coil that output the voltage pulse, which are held in nonvolatile memory 127, are updated. At this time, region 6 is the position of the magnet reference when the previous voltage pulse was generated, and region 5 is the position of the magnet reference when the last voltage pulse was generated. Also, it is assumed that the C-phase detection coil 114 generated the previous voltage pulse, and the C-phase detection coil 114 generated the voltage pulse before the previous one. The voltage pulses that then occur when the magnet reference moves CCW from region 2 to region 1 follow a pattern that would not normally occur when the magnet reference is located in region 6. FIG. Since the detection coil that generated the voltage pulse before the last does not match, none of the correction patterns apply, and as a result, an error is output.
一方、実施の形態3に従う更新処理では、上述したように補正が実行されるため、装置の稼働を継続させることが可能となる。
On the other hand, in the update process according to the third embodiment, since the correction is executed as described above, it is possible to continue the operation of the device.
実施の形態4.
図15は、実施の形態4に従う回転検出器の全体構成を示す図である。図15に示すように、実施の形態4に従う回転検出器101Cは、信号処理回路120に代えて信号処理回路120Cを備える点が図1に示した回転検出器101とは異なる。Embodiment 4.
FIG. 15 is a diagram showing the overall configuration of the rotation detector according to the fourth embodiment. As shown in FIG. 15,rotation detector 101C according to the fourth embodiment differs from rotation detector 101 shown in FIG.
図15は、実施の形態4に従う回転検出器の全体構成を示す図である。図15に示すように、実施の形態4に従う回転検出器101Cは、信号処理回路120に代えて信号処理回路120Cを備える点が図1に示した回転検出器101とは異なる。
FIG. 15 is a diagram showing the overall configuration of the rotation detector according to the fourth embodiment. As shown in FIG. 15,
信号処理回路120Cは、図1に示した信号処理回路120におけるコントローラ125、アダー126、および不揮発性メモリ127を、コントローラ125C、アダー126C、および不揮発性メモリ127Cにそれぞれ置き換えたものである。
The signal processing circuit 120C replaces the controller 125, adder 126 and nonvolatile memory 127 in the signal processing circuit 120 shown in FIG. 1 with a controller 125C, adder 126C and nonvolatile memory 127C, respectively.
不揮発性メモリ127Cは、回転軸115の回転数、電圧パルスが生じたときの各相検出コイルの状態、および電圧パルスを発生した検出コイルの情報(検出コイル番号)の履歴に加えて、補正履歴の情報を記憶するように構成される。補正履歴の情報には、補正が実施されたときの各相検出コイルの状態、および検知されたパルス抜けに関する情報が含まれている。補正が実施されるごとに、補正履歴が更新される。
The nonvolatile memory 127C is configured to store correction history information in addition to the history of the number of rotations of the rotating shaft 115, the state of each phase detection coil when a voltage pulse is generated, and the information (detection coil number) of the detection coil that generated the voltage pulse. The correction history information includes information on the state of each phase detection coil when the correction was performed and on the detected missing pulse. The correction history is updated each time the correction is performed.
不揮発性メモリ127Cは、補正実施カウンタ、およびパルス検出カウンタを有している。補正実施カウンタは、補正が実施された回数をカウントして記憶するように構成される。パルス検出カウンタは、電圧パルスが発生した回数をカウントして記憶するように構成される。
The nonvolatile memory 127C has a correction execution counter and a pulse detection counter. The correction implementation counter is configured to count and store the number of times the correction is implemented. The pulse detection counter is configured to count and store the number of times a voltage pulse has occurred.
コントローラ125Cは、不揮発性メモリ127Cにアクセスし、前回の電圧パルスが生じたときの回転軸115の回転数、前回の電圧パルスを発生したときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報と、前々回の電圧パルスを発生したときの各相検出コイルの状態および当該電圧パルスを出力した検出コイルの情報と、補正実施カウンタおよびパルス検出カウンタのカウント値と、補正履歴とを不揮発性メモリ127Cから読み出す。コントローラ125Cは、読み出したこれらの情報をアダー126Cへ送信する。
The controller 125C has access to non -volatile memory 127c, the rotation axis 115 when the previous voltage pulse occurs, the status of each phase detection coil at the time of the previous voltage pulse, the detection coil that outputs the voltage pulse, and the status of each phase coil when the voltage pulse is generated two times. And the information of the detection coil that outputs the voltage pulse, the count value of the correction implementation counter and the pulse detection counter, and the correction history are read from non -volatile memory 127c. The controller 125C transmits the read information to the adder 126C.
アダー126Cは、コントローラ125Cから受信した情報(今回の電圧パルスの情報および不揮発性メモリ127Cから読み出した情報)に基づいて、変換テーブル(図12および図13)を用いて、更新処理を実行する。この更新処理において、アダー126Cは、パルス検出カウンタのカウント値を1増加(インクリメント)する。
The adder 126C executes update processing using the conversion table (FIGS. 12 and 13) based on the information received from the controller 125C (current voltage pulse information and information read from the nonvolatile memory 127C). In this update process, the adder 126C increments the count value of the pulse detection counter by one.
アダー126Cはさらに、更新処理において、不揮発性メモリ127Cに格納されている各相検出コイルの状態(磁石基準の位置)を補正する処理を行った場合には、補正実施カウンタのカウント値を1増加(インクリメント)するとともに、補正履歴として、補正したときの各相検出コイルの状態、およびパルス抜けが生じたと推定されたときの検出コイルの情報を取得する。
The adder 126C further increments the count value of the correction execution counter by 1 when performing the process of correcting the state of each phase detection coil (the magnet-based position) stored in the nonvolatile memory 127C in the update process, and acquires the state of each phase detection coil at the time of correction and the information on the detection coil at the time when it is estimated that a missing pulse has occurred as a correction history.
続いて、アダー126Cは、パルス検出カウンタのカウント値と補正実施カウンタのカウント値とを比較する。パルス検出カウンタのカウント値に対する補正実施カウンタのカウント値の割合(補正実施カウンタのカウント値/パルス検出カウンタのカウント値)が予め定められた閾値を超える場合には、環境および部品などに異常が発生していることが懸念されるため、アダー126Cはエラーを出力する。
Subsequently, the adder 126C compares the count value of the pulse detection counter and the count value of the correction execution counter. If the ratio of the count value of the correction counter to the count value of the pulse detection counter (count value of correction counter/count value of pulse detection counter) exceeds a predetermined threshold value, the adder 126C outputs an error because there is concern that an abnormality has occurred in the environment, parts, or the like.
アダー126Cは、例えば、各カウンタのカウント値が2進数である場合には、上記割合が閾値として2の20乗分の1を超えたことに応じて、エラーを出力する。なお、上記割合が閾値に至る前にパルス検出カウンタのカウント値が上限に達した場合には、パルス検出カウンタおよび補正実施カウンタの各々は、カウント値を1ビット右シフトすることにより、カウント値を半減させて、カウントアップを継続する。なお、カウント値を調整する方法は、上述した右シフトに限定されず、各カウンタを初期化したり、カウント値を任意の値に調整する方法などを適用することができる。
For example, when the count value of each counter is a binary number, the adder 126C outputs an error when the ratio exceeds 1/2 to the 20th power as a threshold value. If the count value of the pulse detection counter reaches the upper limit before the ratio reaches the threshold, each of the pulse detection counter and the correction execution counter right-shifts the count value by 1 bit to halve the count value and continue counting up. Note that the method of adjusting the count value is not limited to the right shift described above, and a method of initializing each counter or adjusting the count value to an arbitrary value can be applied.
コントローラ125Cは、再度不揮発性メモリ127Cにアクセスし、アダー126Cから受信した情報(カウント値および補正履歴を含む)、および更新後の検出コイルの情報の履歴を不揮発性メモリ127Cに書き込む。
The controller 125C accesses the non-volatile memory 127C again, and writes the information received from the adder 126C (including the count value and correction history) and the history of the updated detection coil information to the non-volatile memory 127C.
以上のように、実施の形態4では、実施の形態1および3で述べた補正を実施できる場合であっても、アダー126Cがエラーを出力するように構成される。これによると、装置の稼働を継続できなくなるが、補正できないような異常が生じる前に装置を安全に停止させることができる。また、補正履歴の情報を不揮発性メモリ127Cに記憶しておくことで、要因箇所の特定に繋がる情報を得ることができる。
As described above, in the fourth embodiment, the adder 126C is configured to output an error even when the corrections described in the first and third embodiments can be performed. According to this, the operation of the apparatus cannot be continued, but the apparatus can be safely stopped before an abnormality that cannot be corrected occurs. Further, by storing correction history information in the non-volatile memory 127C, it is possible to obtain information leading to identification of the factor location.
なお、アダー126Cがエラーを出力するか否かの判定基準は、上記割合に限定されるものではない。例えば、不揮発性メモリ127Cにパルス検出カウンタを実装せず、補正実施カウンタのみを実装しておき、補正実施カウンタのカウント値が予め定められた閾値を超えた場合に、アダー126Cがエラーを出力する構成とすることができる。
Note that the criterion for determining whether the adder 126C outputs an error is not limited to the above ratio. For example, the pulse detection counter is not mounted in the nonvolatile memory 127C, but only the correction counter is mounted, and when the count value of the correction counter exceeds a predetermined threshold value, the adder 126C outputs an error.
また、アダー126Cは、エラーを出力する構成に代えて、装置の稼働を継続しつつ、外部機器を通じて装置の保守点検を促す警告を報知する構成としてもよい。さらに、アダー126Cは、不揮発性メモリ127Cから補正履歴の情報を読み出すことなく、不揮発性メモリ127Cの所定のアドレスに補正履歴の情報を書き込むことも可能である。
The adder 126C may also be configured to issue a warning to prompt maintenance and inspection of the device through an external device while continuing the operation of the device, instead of outputting an error. Furthermore, the adder 126C can write correction history information to a predetermined address in the nonvolatile memory 127C without reading the correction history information from the nonvolatile memory 127C.
本開示は、その発明の範囲内において、各実施の形態を組み合わせたり、各実施の形態を適宜、変形、省略したりすることが可能である。また、上記実施の形態には種々の段階の発明が含まれており、開示される複数の構成要件における適宜な組み合わせにより種々の発明が抽出され得る。
Within the scope of the present disclosure, each embodiment can be combined, modified, or omitted as appropriate. In addition, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.
今回開示された実施の形態は、すべての点で例示であって制限的なものではないと考えられるべきである。本開示により示される技術的範囲は、上記した実施の形態の説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。
The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The technical scope indicated by the present disclosure is indicated by the scope of claims rather than the description of the above-described embodiments, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.
10 CPU、11 RAM、12 ROM、13 I/F装置、14 記憶装置、15 通信バス、101,101A,101B,101C 回転検出器、110 回転検出機構、111 磁石、112 A相検出コイル、113 B相検出コイル、114 C相検出コイル、115 回転軸、120,120A,120B,120C 信号処理回路、121_A,121_B,121_C 全波整流回路、122 定電圧回路、123 Enable回路、124 パルス波形符号判定回路、125,125A,125B,125C コントローラ、126,126A,126C アダー、127,127A,127C 不揮発性メモリ、128 外部回路I/F、129 電源切替回路。
10 CPU, 11 RAM, 12 ROM, 13 I/F device, 14 storage device, 15 communication bus, 101, 101A, 101B, 101C rotation detector, 110 rotation detection mechanism, 111 magnet, 112 A phase detection coil, 113 B phase detection coil, 114 C phase detection coil, 115 rotation shaft, 120, 120A, 120B, 120C signal processing circuit, 121_A, 121_B, 121_C full-wave rectifier circuit, 122 constant voltage circuit, 123 Enable circuit, 124 pulse waveform sign determination circuit, 125, 125A, 125B, 125C controller, 126, 126A, 126C adder, 127, 127A, 127C non-volatile memory, 128 external circuit I/F, 129 Power supply switching circuit.
Claims (9)
- 回転軸の回転方向および回転数を検出する回転検出器であって、
前記回転軸に取り付けられ、前記回転軸の回転を検出する回転検出機構と、
前記回転検出機構と電気的に接続される信号処理回路とを備え、
前記回転検出機構は、
前記回転軸と同期して回転するように構成され、回転方向に配置されたN個の磁極を有する磁石と、
前記磁石の回転方向に沿って予め定められた位相だけ互いにずれた位置に配置されるL個の検出コイルとを含み、Nは2以上の自然数であり、Lは3以上の自然数であり、
前記L個の検出コイルの各々は、前記磁石から印加される磁界を受けて正または負の極性の電圧パルスを発生するように構成され、
前記信号処理回路は、
電圧パルスが発生する毎に、当該電圧パルスの電力から電源電圧を生成する定電圧回路と、
前記電源電圧を受けて動作するコントローラおよび不揮発性メモリとを含み、
前記不揮発性メモリは、電圧パルスを発生したときの前記L個の検出コイルの状態、前記回転軸の回転数、および、当該電圧パルスを発生した検出コイルの情報の履歴を記憶するように構成され、
前記コントローラは、電圧パルスが発生する毎に、前記L個の検出コイルの状態、前記回転軸の回転数、および、当該電圧パルスを発生した検出コイルの情報を取得して前記不揮発性メモリを更新する処理を実行するように構成され、
前記更新する処理において、前記コントローラは、
今回の電圧パルスの情報と、前記不揮発性メモリに保持されている、前回の電圧パルスを発生したときの前記L個の検出コイルの状態、前々回の電圧パルスを発生したときの前記L個の検出コイルの状態、および、前記前々回の電圧パルスを発生した検出コイルの情報の履歴とを参照することにより、電圧パルスが欠落するパルス抜けを検知するとともに、前記不揮発性メモリに保持される前記L個の検出コイルの状態および前記回転軸の回転数を補正する、回転検出器。 A rotation detector that detects the direction of rotation and the number of rotations of a rotating shaft,
a rotation detection mechanism attached to the rotating shaft for detecting rotation of the rotating shaft;
A signal processing circuit electrically connected to the rotation detection mechanism,
The rotation detection mechanism is
a magnet configured to rotate synchronously with the rotating shaft and having N magnetic poles arranged in the direction of rotation;
L detection coils arranged at positions shifted from each other by a predetermined phase along the direction of rotation of the magnet, N is a natural number of 2 or more, L is a natural number of 3 or more,
each of the L sensing coils is configured to receive a magnetic field applied from the magnet and generate a voltage pulse of positive or negative polarity;
The signal processing circuit is
a constant voltage circuit that generates a power supply voltage from the power of the voltage pulse each time the voltage pulse is generated;
including a controller and a non-volatile memory that operate upon receiving the power supply voltage,
The nonvolatile memory is configured to store the state of the L detection coils when the voltage pulse is generated, the number of revolutions of the rotating shaft, and the history of information of the detection coil that generated the voltage pulse,
The controller acquires the states of the L detection coils, the number of rotations of the rotating shaft, and information about the detection coil that generated the voltage pulse each time a voltage pulse is generated, and updates the nonvolatile memory.
In the updating process, the controller
A rotation detector that detects a missing pulse in which a voltage pulse is missing and corrects the state of the L detection coils and the number of revolutions of the rotating shaft held in the nonvolatile memory by referring to the current voltage pulse information, the state of the L detection coils when the previous voltage pulse was generated, the state of the L detection coils when the voltage pulse was generated before the previous time, and the history of the information of the detection coils when the voltage pulse was generated the time before last, which are held in the nonvolatile memory. - 前記コントローラは、前記L個の検出コイルの各々の状態を、正の極性の電圧パルスを発生したときに第1の論理レベルに変化させ、かつ、負の極性の電圧パルスを発生したときに第2の論理レベルに変化させるとともに、前記L個の検出コイルの状態から前記磁石の回転位置を推定するように構成され、
前記更新する処理において、前記コントローラは、
前記不揮発性メモリに保持されている前記前回の電圧パルスを発生したときの前記L個の検出コイルの状態および前記前々回の電圧パルスを発生したときの前記L個の検出コイルの状態の各々から推定される前記磁石の回転位置と、前記前々回の電圧パルスを発生した検出コイルの情報の履歴とを参照することにより、前記パルス抜けを検知するとともに、前記磁石の回転位置の遷移を推定し、
推定された前記磁石の回転位置の遷移に基づいて、前記不揮発性メモリに保持される前記L個の検出コイルの状態および前記回転軸の回転数を補正する、請求項1に記載の回転検出器。 the controller is configured to change the state of each of the L sensing coils to a first logic level upon generation of a positive polarity voltage pulse and to a second logic level upon generation of a negative polarity voltage pulse, and to estimate the rotational position of the magnet from the states of the L sensing coils;
In the updating process, the controller
detecting the missing pulse and estimating the transition of the rotational position of the magnet by referring to the rotational position of the magnet estimated from each of the states of the L detection coils when the previous voltage pulse was generated and the state of the L detection coils when the voltage pulse was generated the second last time held in the nonvolatile memory, and the history of information of the detection coil that generated the voltage pulse of the time before the last time;
2. The rotation detector according to claim 1, wherein the state of said L detection coils and the number of revolutions of said rotating shaft, which are held in said nonvolatile memory, are corrected based on the estimated transition of the rotational position of said magnet. - 前記コントローラは、前記不揮発性メモリに保持されている、前回の電圧パルスを発生したときの前記L個の検出コイルの状態、前々回の電圧パルスを発生したときの前記L個の検出コイルの状態、および、前記前々回の電圧パルスを発生した検出コイルの情報の履歴とを参照することにより、前記回転軸が第1の回転方向に回転しているときに発生した前記パルス抜けを検知して、前記不揮発性メモリに保持される前記L個の検出コイルの状態および前記回転軸の回転数を補正する、請求項1または2に記載の回転検出器。 The controller refers to the state of the L detection coils when the previous voltage pulse was generated, the state of the L detection coils when the voltage pulse was generated the second last time, and the information history of the detection coils that generated the voltage pulse the second last time, which are held in the nonvolatile memory, thereby detecting the missing pulse that occurred while the rotating shaft was rotating in the first rotation direction, and detecting the state of the L detecting coils and the number of rotations of the rotating shaft held in the nonvolatile memory. 3. The rotation detector according to claim 1 or 2, which corrects for .
- 前記コントローラは、前記不揮発性メモリに保持されている、前回の電圧パルスを発生したときの前記L個の検出コイルの状態、前々回の電圧パルスを発生したときの前記L個の検出コイルの状態、および、前記前々回の電圧パルスを発生した検出コイルの情報の履歴とを参照することにより、前記回転軸が第1の回転方向から第2の方向に反転した後に少なくとも2回連続して発生した前記パルス抜けを検知して、前記不揮発性メモリに保持される前記L個の検出コイルの状態および前記回転軸の回転数を補正する、請求項1または2に記載の回転検出器。 The controller refers to the state of the L detection coils when the previous voltage pulse was generated, the state of the L detection coils when the voltage pulse was generated the second last time, and the information history of the detection coils that generated the voltage pulse the second last time, which are held in the nonvolatile memory, thereby detecting the missing pulses that occurred at least twice consecutively after the rotation axis was reversed from the first rotation direction to the second direction, and the L detections held in the nonvolatile memory. 3. The rotation detector according to claim 1, wherein the state of the coil and the number of revolutions of the rotating shaft are corrected.
- 前記不揮発性メモリは、さらに、前回の前記更新する処理において前記補正を実施したか否かを示す情報を保持するように構成され、
前記コントローラは、今回の前記更新処理において前記補正を行う場合において、前回の前記更新処理において前記補正を実施していたときには、エラーを出力する、請求項1から4のいずれか1項に記載の回転検出器。 The nonvolatile memory is further configured to hold information indicating whether or not the correction was performed in the previous updating process,
5. The rotation detector according to any one of claims 1 to 4, wherein when the correction is performed in the current update process, the controller outputs an error when the correction was performed in the previous update process. - 前記信号処理回路は、前記補正が実施された回数をカウントするカウンタを有しており、
前記コントローラは、前記カウンタのカウント値が閾値を超えたときに、エラーを出力する、請求項1から4のいずれか1項に記載の回転検出器。 The signal processing circuit has a counter that counts the number of times the correction is performed,
5. The rotation detector according to claim 1, wherein said controller outputs an error when the count value of said counter exceeds a threshold. - 前記信号処理回路は、電圧パルスが発生した回数をカウントする第1のカウンタと、前記補正が実施された回数をカウントする第2のカウンタとを有しており、
前記コントローラは、前記第1のカウンタのカウント値に対する前記第2のカウンタのカウント値の比率が閾値を超えたときに、エラーを出力する、請求項1から4のいずれか1項に記載の回転検出器。 The signal processing circuit has a first counter that counts the number of times the voltage pulse is generated and a second counter that counts the number of times the correction is performed,
5. The rotation detector according to claim 1, wherein said controller outputs an error when a ratio of the count value of said second counter to the count value of said first counter exceeds a threshold. - 前記不揮発性メモリは、さらに、前記補正を実施したときの前記L個の検出コイルの状体、および、前記パルス抜けに関する情報を保持するように構成され、
前記コントローラは、前記補正が実施されたときには、前記補正履歴を更新する、請求項1から7のいずれか1項に記載の回転検出器。 The nonvolatile memory is further configured to retain information on the shape of the L detection coils and the missing pulse when the correction is performed,
8. The rotation detector according to any one of claims 1 to 7, wherein said controller updates said correction history when said correction is performed. - 前記コントローラは、前記前回の電圧パルスを発生した検出コイルと、前記前々回の電圧パルスを発生した検出コイルとが同一であった場合には、前記不揮発性メモリを更新しない、請求項1から8のいずれか1項に記載の回転検出器。 The rotation detector according to any one of claims 1 to 8, wherein the controller does not update the non-volatile memory when the detection coil that generated the previous voltage pulse and the detection coil that generated the voltage pulse before the previous one are the same.
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